Wireshark User’s Guide

Version 2.9.0


Table of Contents

Preface
1. Foreword
2. Who should read this document?
3. Acknowledgements
4. About this document
5. Where to get the latest copy of this document?
6. Providing feedback about this document
7. Typographic Conventions
7.1. Admonitions
7.2. Shell Prompt and Source Code Examples
1. Introduction
1.1. What is Wireshark?
1.1.1. Some intended purposes
1.1.2. Features
1.1.3. Live capture from many different network media
1.1.4. Import files from many other capture programs
1.1.5. Export files for many other capture programs
1.1.6. Many protocol dissectors
1.1.7. Open Source Software
1.1.8. What Wireshark is not
1.2. System Requirements
1.2.1. Microsoft Windows
1.2.2. UNIX / Linux
1.3. Where to get Wireshark
1.4. A brief history of Wireshark
1.5. Development and maintenance of Wireshark
1.6. Reporting problems and getting help
1.6.1. Website
1.6.2. Wiki
1.6.3. Q&A Site
1.6.4. FAQ
1.6.5. Mailing Lists
1.6.6. Reporting Problems
1.6.7. Reporting Crashes on UNIX/Linux platforms
1.6.8. Reporting Crashes on Windows platforms
2. Building and Installing Wireshark
2.1. Introduction
2.2. Obtaining the source and binary distributions
2.3. Installing Wireshark under Windows
2.3.1. Installation Components
2.3.2. Additional Tasks
2.3.3. Install Location
2.3.4. Installing WinPcap
2.3.5. Windows installer command line options
2.3.6. Manual WinPcap Installation
2.3.7. Update Wireshark
2.3.8. Update WinPcap
2.3.9. Uninstall Wireshark
2.3.10. Uninstall WinPcap
2.4. Installing Wireshark under macOS
2.5. Building Wireshark from source under UNIX
2.6. Installing the binaries under UNIX
2.6.1. Installing from RPMs under Red Hat and alike
2.6.2. Installing from debs under Debian, Ubuntu and other Debian derivatives
2.6.3. Installing from portage under Gentoo Linux
2.6.4. Installing from packages under FreeBSD
2.7. Troubleshooting during the build and install on Unix
2.8. Building from source under Windows
3. User Interface
3.1. Introduction
3.2. Start Wireshark
3.3. The Main window
3.3.1. Main Window Navigation
3.4. The Menu
3.5. The “File” menu
3.6. The “Edit” Menu
3.7. The “View” Menu
3.8. The “Go” Menu
3.9. The “Capture” menu
3.10. The “Analyze” Menu
3.11. The “Statistics” Menu
3.12. The “Telephony” Menu
3.13. The “Tools” Menu
3.14. The “Help” Menu
3.15. The “Main” Toolbar
3.16. The “Filter” Toolbar
3.17. The “Packet List” Pane
3.18. The “Packet Details” Pane
3.19. The “Packet Bytes” Pane
3.20. The Statusbar
4. Capturing Live Network Data
4.1. Introduction
4.2. Prerequisites
4.3. Start Capturing
4.4. The “Capture Interfaces” dialog box
4.5. The “Capture Options” dialog box
4.5.1. Capture frame
4.5.2. Capture File(s) frame
4.5.3. Stop Capture…​ frame
4.5.4. Display Options frame
4.5.5. Name Resolution frame
4.5.6. Buttons
4.6. The “Edit Interface Settings” dialog box
4.7. The “Compile Results” dialog box
4.8. The “Add New Interfaces” dialog box
4.8.1. Add or remove pipes
4.8.2. Add or hide local interfaces
4.8.3. Add or hide remote interfaces
4.9. The “Remote Capture Interfaces” dialog box
4.9.1. Remote Capture Interfaces
4.9.2. Remote Capture Settings
4.10. The “Interface Details” dialog box
4.11. Capture files and file modes
4.12. Link-layer header type
4.13. Filtering while capturing
4.13.1. Automatic Remote Traffic Filtering
4.14. While a Capture is running …​
4.14.1. Stop the running capture
4.14.2. Restart a running capture
5. File Input, Output, and Printing
5.1. Introduction
5.2. Open capture files
5.2.1. The “Open Capture File” dialog box
5.2.2. Input File Formats
5.3. Saving captured packets
5.3.1. The “Save Capture File As” dialog box
5.3.2. Output File Formats
5.4. Merging capture files
5.4.1. The “Merge with Capture File” dialog box
5.5. Import hex dump
5.5.1. The “Import from Hex Dump” dialog box
5.6. File Sets
5.6.1. The “List Files” dialog box
5.7. Exporting data
5.7.1. The “Export as Plain Text File” dialog box
5.7.2. The “Export as PostScript File” dialog box
5.7.3. The “Export as CSV (Comma Separated Values) File” dialog box
5.7.4. The “Export as C Arrays (packet bytes) file” dialog box
5.7.5. The “Export as PSML File” dialog box
5.7.6. The “Export as PDML File” dialog box
5.7.7. The “Export selected packet bytes” dialog box
5.7.8. The “Export Objects” dialog box
5.8. Printing packets
5.8.1. The “Print” dialog box
5.9. The “Packet Range” frame
5.10. The Packet Format frame
6. Working with captured packets
6.1. Viewing packets you have captured
6.2. Pop-up menus
6.2.1. Pop-up menu of the “Packet List” column header
6.2.2. Pop-up menu of the “Packet List” pane
6.2.3. Pop-up menu of the “Packet Details” pane
6.3. Filtering packets while viewing
6.4. Building display filter expressions
6.4.1. Display filter fields
6.4.2. Comparing values
6.4.3. Combining expressions
6.4.4. Slice Operator
6.4.5. Membership Operator
6.4.6. Functions
6.4.7. A Common Mistake
6.4.8. Sometimes Fields Change Names
6.5. The “Filter Expression” dialog box
6.6. Defining and saving filters
6.7. Defining and saving filter macros
6.8. Finding packets
6.8.1. The “Find Packet” dialog box
6.8.2. The “Find Next” command
6.8.3. The “Find Previous” command
6.9. Go to a specific packet
6.9.1. The “Go Back” command
6.9.2. The “Go Forward” command
6.9.3. The “Go to Packet” dialog box
6.9.4. The “Go to Corresponding Packet” command
6.9.5. The “Go to First Packet” command
6.9.6. The “Go to Last Packet” command
6.10. Marking packets
6.11. Ignoring packets
6.12. Time display formats and time references
6.12.1. Packet time referencing
7. Advanced Topics
7.1. Introduction
7.2. Following Protocol Streams
7.3. Show Packet Bytes
7.4. Expert Information
7.4.1. Expert Info Entries
7.4.2. “Expert Info” dialog
7.4.3. “Colorized” Protocol Details Tree
7.4.4. “Expert” Packet List Column (optional)
7.5. TCP Analysis
7.6. Time Stamps
7.6.1. Wireshark internals
7.6.2. Capture file formats
7.6.3. Accuracy
7.7. Time Zones
7.7.1. Set your computer’s time correctly!
7.7.2. Wireshark and Time Zones
7.8. Packet Reassembly
7.8.1. What is it?
7.8.2. How Wireshark handles it
7.8.3. TCP Reassembly
7.9. Name Resolution
7.9.1. Name Resolution drawbacks
7.9.2. Ethernet name resolution (MAC layer)
7.9.3. IP name resolution (network layer)
7.9.4. TCP/UDP port name resolution (transport layer)
7.9.5. VLAN ID resolution
7.9.6. SS7 point code resolution
7.10. Checksums
7.10.1. Wireshark checksum validation
7.10.2. Checksum offloading
8. Statistics
8.1. Introduction
8.2. The “Capture File Properties” Window
8.3. Resolved Addresses
8.4. The “Protocol Hierarchy” Window
8.5. Conversations
8.5.1. The “Conversations” Window
8.6. Endpoints
8.6.1. The “Endpoints” Window
8.7. Packet Lengths
8.8. The “I/O Graph” Window
8.9. Service Response Time
8.9.1. The “Service Response Time DCE-RPC” Window
8.10. DHCP (BOOTP) Statistics
8.11. ONC-RPC Programs
8.12. 29West
8.13. ANCP
8.14. BACnet
8.15. Collectd
8.16. DNS
8.17. Flow Graph
8.18. HART-IP
8.19. HPFEEDS
8.20. HTTP Statistics
8.20.1. HTTP Packet Counter
8.20.2. HTTP Requests
8.20.3. HTTP Load Distribution
8.20.4. HTTP Request Sequences
8.21. HTTP2
8.22. Sametime
8.23. TCP Stream Graphs
8.24. UDP Multicast Graphs
8.25. F5
8.26. IPv4 Statistics
8.27. IPv6 Statistics
9. Telephony
9.1. Introduction
9.2. VoIP Calls
9.3. ANSI
9.4. GSM
9.5. IAX2 Stream Analysis
9.6. ISUP Messages
9.7. LTE
9.7.1. LTE MAC Traffic Statistics
9.7.2. LTE RLC Graph
9.7.3. LTE RLC Traffic Statistics
9.8. MTP3
9.9. Osmux
9.10. RTP Analysis
9.11. RTSP
9.12. SCTP
9.13. SMPP Operations
9.14. UCP Messages
9.15. H.225
9.16. SIP Flows
9.17. SIP Statistics
9.18. WAP-WSP Packet Counter
10. Wireless
10.1. Introduction
10.2. Bluetooth ATT Server Attributes
10.3. Bluetooth Devices
10.4. Bluetooth HCI Summary
10.5. WLAN Traffic
11. Customizing Wireshark
11.1. Introduction
11.2. Start Wireshark from the command line
11.3. Packet colorization
11.4. Control Protocol dissection
11.4.1. The “Enabled Protocols” dialog box
11.4.2. User Specified Decodes
11.4.3. Show User Specified Decodes
11.5. Preferences
11.5.1. Interface Options
11.6. Configuration Profiles
11.7. User Table
11.8. Display Filter Macros
11.9. ESS Category Attributes
11.10. MaxMind Database Paths
11.11. IKEv2 decryption table
11.12. Object Identifiers
11.13. PRES Users Context List
11.14. SCCP users Table
11.15. SMI (MIB and PIB) Modules
11.16. SMI (MIB and PIB) Paths
11.17. SNMP Enterprise Specific Trap Types
11.18. SNMP users Table
11.19. Tektronix K12xx/15 RF5 protocols Table
11.20. User DLTs protocol table
12. MATE
12.1. Introduction
12.2. Getting Started
12.3. MATE Manual
12.3.1. Introduction
12.3.2. Attribute Value Pairs
12.3.3. AVP lists
12.3.4. MATE Analysis
12.3.5. About MATE
12.4. MATE’s configuration tutorial
12.4.1. A Gop for DNS requests
12.4.2. A Gop for HTTP requests
12.4.3. Getting DNS and HTTP together into a Gog
12.4.4. Separating requests from multiple users
12.5. MATE configuration examples
12.5.1. TCP session
12.5.2. a Gog for a complete FTP session
12.5.3. using RADIUS to filter SMTP traffic of a specific user
12.5.4. H323 Calls
12.5.5. MMS
12.6. MATE’s configuration library
12.6.1. General use protocols
12.6.2. VoIP/Telephony
12.7. MATE’s reference manual
12.7.1. Attribute Value Pairs
12.7.2. Attribute/Value Pair List (AVPL)
12.8. Configuration AVPLs
12.8.1. Pdsu’s configuration actions
A. Wireshark Messages
A.1. Packet List Messages
A.1.1. [Malformed Packet]
A.1.2. [Packet size limited during capture]
A.2. Packet Details Messages
A.2.1. [Response in frame: 123]
A.2.2. [Request in frame: 123]
A.2.3. [Time from request: 0.123 seconds]
A.2.4. [Stream setup by PROTOCOL (frame 123)]
B. Files and Folders
B.1. Capture Files
B.1.1. Libpcap File Contents
B.1.2. Not Saved in the Capture File
B.2. Configuration File and Plugin Folders
B.2.1. Folders on Windows
B.2.2. Folders on Unix-like systems
B.3. Configuration Files
B.4. Plugin folders
B.5. Windows folders
B.5.1. Windows profiles
B.5.2. Windows roaming profiles
B.5.3. Windows temporary folder
C. Protocols and Protocol Fields
D. Related command line tools
D.1. Introduction
D.2. tshark: Terminal-based Wireshark
D.3. tcpdump: Capturing with “tcpdump” for viewing with Wireshark
D.4. dumpcap: Capturing with “dumpcap” for viewing with Wireshark
D.5. capinfos: Print information about capture files
D.6. rawshark: Dump and analyze network traffic.
D.7. editcap: Edit capture files
D.8. mergecap: Merging multiple capture files into one
D.9. text2pcap: Converting ASCII hexdumps to network captures
D.10. reordercap: Reorder a capture file
13. This Document’s License (GPL)

List of Figures

1.1. Wireshark captures packets and lets you examine their contents.
3.1. The Main window
3.2. The Menu
3.3. The “File” Menu
3.4. The “Edit” Menu
3.5. The “View” Menu
3.6. The “Go” Menu
3.7. The “Capture” Menu
3.8. The “Analyze” Menu
3.9. The “Statistics” Menu
3.10. The “Telephony” Menu
3.11. The “Tools” Menu
3.12. The “Help” Menu
3.13. The “Main” toolbar
3.14. The “Filter” toolbar
3.15. The “Packet List” pane
3.16. The “Packet Details” pane
3.17. The “Packet Bytes” pane
3.18. The “Packet Bytes” pane with tabs
3.19. The initial Statusbar
3.20. The Statusbar with a loaded capture file
3.21. The Statusbar with a configuration profile menu
3.22. The Statusbar with a selected protocol field
3.23. The Statusbar with a display filter message
4.1. The “Capture Interfaces” dialog box on Microsoft Windows
4.2. The “Capture Interfaces” dialog box on Unix/Linux
4.3. The “Capture Options” dialog box
4.4. The “Edit Interface Settings” dialog box
4.5. The “Compile Results” dialog box
4.6. The “Add New Interfaces” dialog box
4.7. The “Add New Interfaces - Pipes” dialog box
4.8. The “Add New Interfaces - Local Interfaces” dialog box
4.9. The “Add New Interfaces - Remote Interfaces” dialog box
4.10. The “Remote Capture Interfaces” dialog box
4.11. The “Remote Capture Settings” dialog box
4.12. The “Interface Details” dialog box
4.13. Capture output options
4.14. The “Capture Information” dialog box
5.1. “Open” on Microsoft Windows
5.2. “Open” - Linux and UNIX
5.3. “Save” on Microsoft Windows
5.4. “Save” on Linux and UNIX
5.5. “Merge” on Microsoft Windows
5.6. “Merge” on Linux and UNIX
5.7. The “Import from Hex Dump” dialog
5.8. The “List Files” dialog box
5.9. The “Export as Plain Text File” dialog box
5.10. The “Export as PostScript File” dialog box
5.11. The “Export as PSML File” dialog box
5.12. The “Export as PDML File” dialog box
5.13. The “Export Selected Packet Bytes” dialog box
5.14. The “Export Objects” dialog box
5.15. The “Print” dialog box
5.16. The “Packet Range” frame
5.17. The “Packet Format” frame
6.1. Wireshark with a TCP packet selected for viewing
6.2. Viewing a packet in a separate window
6.3. Pop-up menu of the “Packet List” column header
6.4. Pop-up menu of the “Packet List” pane
6.5. Pop-up menu of the “Packet Details” pane
6.6. Filtering on the TCP protocol
6.7. The “Filter Expression” dialog box
6.8. The “Capture Filters” and “Display Filters” dialog boxes
6.9. The “Find Packet” dialog box
6.10. The “Go To Packet” dialog box
6.11. Wireshark showing a time referenced packet
7.1. The “Follow TCP Stream” dialog box
7.2. The “Expert Info” dialog box
7.3. The “Colorized” protocol details tree
7.4. The “Expert” packet list column
7.5. “TCP Analysis” packet detail items
7.6. The “Packet Bytes” pane with a reassembled tab
8.1. The “Capture File Properties” window
8.2. The “Protocol Hierarchy” Window
8.3. The “Conversations” window
8.4. The “Endpoints” window
8.5. The “IO Graphs” window
8.6. The “Compute DCE-RPC statistics” window
8.7. The “DCE-RPC Statistic for …​” window
8.8. The “HTTP Request Sequences” window
9.1. The “LTE MAC Traffic Statistics” window
9.2. The “LTE RLC Traffic Statistics” window
9.3. The “RTP Stream Analysis” window
10.1. The “WLAN Traffic Statistics” window
11.1. The “Coloring Rules” dialog box
11.2. A color chooser
11.3. Using color filters with Wireshark
11.4. The “Enabled Protocols” dialog box
11.5. The “Decode As” dialog box
11.6. The “Decode As: Show” dialog box
11.7. The preferences dialog box
11.8. The interface options dialog box
11.9. The configuration profiles dialog box

List of Tables

1. Typographic Conventions
3.1. Keyboard Navigation
3.2. File menu items
3.3. Edit menu items
3.4. View menu items
3.5. Internals menu items
3.6. Go menu items
3.7. Capture menu items
3.8. Analyze menu items
3.9. Statistics menu items
3.10. Telephony menu items
3.11. Tools menu items
3.12. Help menu items
3.13. Main toolbar items
3.14. Filter toolbar items
3.15. Related packet symbols
4.1. Capture file mode selected by capture options
6.1. The menu items of the “Packet List” column header pop-up menu
6.2. The menu items of the “Packet List” pop-up menu
6.3. The menu items of the “Packet Details” pop-up menu
6.4. Display Filter comparison operators
6.5. Display Filter Logical Operations
6.6. Display Filter Functions
7.1. Some example expert infos
7.2. Time zone examples for UTC arrival times (without DST)
B.1. Configuration files overview

List of Examples

4.1. A capture filter for telnet that captures traffic to and from a particular host
4.2. Capturing all telnet traffic not from 10.0.0.5
11.1. Help information available from Wireshark

Preface

1. Foreword

Wireshark is one of those programs that many network managers would love to be able to use, but they are often prevented from getting what they would like from Wireshark because of the lack of documentation.

This document is part of an effort by the Wireshark team to improve the usability of Wireshark.

We hope that you find it useful and look forward to your comments.

2. Who should read this document?

The intended audience of this book is anyone using Wireshark.

This book will explain all the basics and also some of the advanced features that Wireshark provides. As Wireshark has become a very complex program since the early days, not every feature of Wireshark may be explained in this book.

This book is not intended to explain network sniffing in general and it will not provide details about specific network protocols. A lot of useful information regarding these topics can be found at the Wireshark Wiki at https://wiki.wireshark.org/.

By reading this book, you will learn how to install Wireshark, how to use the basic elements of the graphical user interface (such as the menu) and what’s behind some of the advanced features that are not always obvious at first sight. It will hopefully guide you around some common problems that frequently appear for new (and sometimes even advanced) users of Wireshark.

3. Acknowledgements

The authors would like to thank the whole Wireshark team for their assistance. In particular, the authors would like to thank:

  • Gerald Combs, for initiating the Wireshark project and funding to do this documentation.
  • Guy Harris, for many helpful hints and a great deal of patience in reviewing this document.
  • Gilbert Ramirez, for general encouragement and helpful hints along the way.

The authors would also like to thank the following people for their helpful feedback on this document:

  • Pat Eyler, for his suggestions on improving the example on generating a backtrace.
  • Martin Regner, for his various suggestions and corrections.
  • Graeme Hewson, for a lot of grammatical corrections.

The authors would like to acknowledge those man page and README authors for the Wireshark project from who sections of this document borrow heavily:

4. About this document

This book was originally developed by Richard Sharpe with funds provided from the Wireshark Fund. It was updated by Ed Warnicke and more recently redesigned and updated by Ulf Lamping.

It was originally written in DocBook/XML and converted to AsciiDoc by Gerald Combs.

5. Where to get the latest copy of this document?

The latest copy of this documentation can always be found at https://www.wireshark.org/docs/.

6. Providing feedback about this document

Should you have any feedback about this document, please send it to the authors through wireshark-dev[AT]wireshark.org.

7. Typographic Conventions

The following table shows the typographic conventions that are used in this guide.

Table 1. Typographic Conventions

Style Description Example

Italic

File names, folder names, and extensions

C:\Development\wireshark.

Monospace

Commands, flags, and environment variables

CMake’s -G option.

Bold Monospace

Commands that should be run by the user

Run cmake -G Ninja ...

Button

Dialog and window buttons

Press Launch to go to the Moon.

Key

Keyboard shortcut

Press Ctrl+Down to move to the next packet.

Menu

Menu item

Select GoNext Packet to move to the next packet.


7.1. Admonitions

Important and notable items are marked as follows:

[Warning] This is a warning

You should pay attention to a warning, otherwise data loss might occur.

[Note] This is a note

A note will point you to common mistakes and things that might not be obvious.

[Tip] This is a tip

Tips are helpful for your everyday work using Wireshark.

7.2. Shell Prompt and Source Code Examples

Bourne shell, normal user. 

$ # This is a comment
$ git config --global log.abbrevcommit true

Bourne shell, root user. 

# # This is a comment
# ninja install

Command Prompt (cmd.exe). 

>rem This is a comment
>cd C:\Development

PowerShell. 

PS$># This is a comment
PS$>choco list -l

C Source Code. 

#include "config.h"

/* This method dissects foos */
static int
dissect_foo_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_)
{
    /* TODO: implement your dissecting code */
    return tvb_captured_length(tvb);
}

Chapter 1. Introduction

1.1. What is Wireshark?

Wireshark is a network packet analyzer. A network packet analyzer will try to capture network packets and tries to display that packet data as detailed as possible.

You could think of a network packet analyzer as a measuring device used to examine what’s going on inside a network cable, just like a voltmeter is used by an electrician to examine what’s going on inside an electric cable (but at a higher level, of course).

In the past, such tools were either very expensive, proprietary, or both. However, with the advent of Wireshark, all that has changed.

Wireshark is perhaps one of the best open source packet analyzers available today.

1.1.1. Some intended purposes

Here are some examples people use Wireshark for:

  • Network administrators use it to troubleshoot network problems
  • Network security engineers use it to examine security problems
  • QA engineers use it to verify network applications
  • Developers use it to debug protocol implementations
  • People use it to learn network protocol internals

Beside these examples Wireshark can be helpful in many other situations too.

1.1.2. Features

The following are some of the many features Wireshark provides:

  • Available for UNIX and Windows.
  • Capture live packet data from a network interface.
  • Open files containing packet data captured with tcpdump/WinDump, Wireshark, and a number of other packet capture programs.
  • Import packets from text files containing hex dumps of packet data.
  • Display packets with very detailed protocol information.
  • Save packet data captured.
  • Export some or all packets in a number of capture file formats.
  • Filter packets on many criteria.
  • Search for packets on many criteria.
  • Colorize packet display based on filters.
  • Create various statistics.
  • …​and a lot more!

However, to really appreciate its power you have to start using it.

Figure 1.1, “Wireshark captures packets and lets you examine their contents.” shows Wireshark having captured some packets and waiting for you to examine them.

Figure 1.1. Wireshark captures packets and lets you examine their contents.

ws main

1.1.3. Live capture from many different network media

Wireshark can capture traffic from many different network media types - and despite its name - including wireless LAN as well. Which media types are supported, depends on many things like the operating system you are using. An overview of the supported media types can be found at https://wiki.wireshark.org/CaptureSetup/NetworkMedia.

1.1.4. Import files from many other capture programs

Wireshark can open packets captured from a large number of other capture programs. For a list of input formats see Section 5.2.2, “Input File Formats”.

1.1.5. Export files for many other capture programs

Wireshark can save packets captured in a large number of formats of other capture programs. For a list of output formats see Section 5.3.2, “Output File Formats”.

1.1.6. Many protocol dissectors

There are protocol dissectors (or decoders, as they are known in other products) for a great many protocols: see Appendix C, Protocols and Protocol Fields.

1.1.7. Open Source Software

Wireshark is an open source software project, and is released under the GNU General Public License (GPL). You can freely use Wireshark on any number of computers you like, without worrying about license keys or fees or such. In addition, all source code is freely available under the GPL. Because of that, it is very easy for people to add new protocols to Wireshark, either as plugins, or built into the source, and they often do!

1.1.8. What Wireshark is not

Here are some things Wireshark does not provide:

  • Wireshark isn’t an intrusion detection system. It will not warn you when someone does strange things on your network that he/she isn’t allowed to do. However, if strange things happen, Wireshark might help you figure out what is really going on.
  • Wireshark will not manipulate things on the network, it will only “measure” things from it. Wireshark doesn’t send packets on the network or do other active things (except for name resolutions, but even that can be disabled).

1.2. System Requirements

The amount of resources Wireshark needs depends on your environment and on the size of the capture file you are analyzing. The values below should be fine for small to medium-sized capture files no more than a few hundred MB. Larger capture files will require more memory and disk space.

[Note] Busy networks mean large captures

Working with a busy network can easily produce huge capture files. Capturing on a gigabit or even 100 megabit network can produce hundreds of megabytes of capture data in a short time. A fast processor, lots of memory and disk space is always a good idea.

If Wireshark runs out of memory it will crash. See https://wiki.wireshark.org/KnownBugs/OutOfMemory for details and workarounds.

Although Wireshark captures packets using a separate process the main interface is single-threaded and won’t benefit much from multi-core systems.

1.2.1. Microsoft Windows

  • The current version of Wireshark should support any version of Windows that is still within its extended support lifetime. At the time of writing this includes Windows 10, 8, 7, Vista, Server 2016, Server 2012 R2, Server 2012, Server 2008 R2, and Server 2008.
  • Any modern 64-bit AMD64/x86-64 or 32-bit x86 processor.
  • 400 MB available RAM. Larger capture files require more RAM.
  • 300 MB available disk space. Capture files require additional disk space.
  • 1024 × 768 (1280 × 1024 or higher recommended) resolution with at least 16-bit color. 8-bit color should work but user experience will be degraded. Power users will find multiple monitors useful.
  • A supported network card for capturing

Older versions of Windows which are outside Microsoft’s extended lifecycle support window are no longer supported. It is often difficult or impossible to support these systems due to circumstances beyond our control, such as third party libraries on which we depend or due to necessary features that are only present in newer versions of Windows (such as hardened security or memory management).

Wireshark 1.12 was the last release branch to support Windows Server 2003. Wireshark 1.10 was the last branch to officially support Windows XP. See the Wireshark release lifecycle page for more details.

1.2.2. UNIX / Linux

Wireshark runs on most UNIX and UNIX-like platforms including macOS and Linux. The system requirements should be comparable to the Windows values listed above.

Binary packages are available for most Unices and Linux distributions including the following platforms:

  • Apple macOS
  • Debian GNU/Linux
  • FreeBSD
  • Gentoo Linux
  • HP-UX
  • Mandriva Linux
  • NetBSD
  • OpenPKG
  • Red Hat Enterprise/Fedora Linux
  • Sun Solaris/i386
  • Sun Solaris/SPARC
  • Canonical Ubuntu

If a binary package is not available for your platform you can download the source and try to build it. Please report your experiences to wireshark-dev[AT]wireshark.org.

1.3. Where to get Wireshark

You can get the latest copy of the program from the Wireshark website at https://www.wireshark.org/download.html. The download page should automatically highlight the appropriate download for your platform and direct you to the nearest mirror. Official Windows and macOS installers are signed by the Wireshark Foundation.

A new Wireshark version typically becomes available each month or two.

If you want to be notified about new Wireshark releases you should subscribe to the wireshark-announce mailing list. You will find more details in Section 1.6.5, “Mailing Lists”.

1.4. A brief history of Wireshark

In late 1997 Gerald Combs needed a tool for tracking down network problems and wanted to learn more about networking so he started writing Ethereal (the original name of the Wireshark project) as a way to solve both problems.

Ethereal was initially released after several pauses in development in July 1998 as version 0.2.0. Within days patches, bug reports, and words of encouragement started arriving and Ethereal was on its way to success.

Not long after that Gilbert Ramirez saw its potential and contributed a low-level dissector to it.

In October, 1998 Guy Harris was looking for something better than tcpview so he started applying patches and contributing dissectors to Ethereal.

In late 1998 Richard Sharpe, who was giving TCP/IP courses, saw its potential on such courses and started looking at it to see if it supported the protocols he needed. While it didn’t at that point new protocols could be easily added. So he started contributing dissectors and contributing patches.

The list of people who have contributed to the project has become very long since then, and almost all of them started with a protocol that they needed that Wireshark or did not already handle. So they copied an existing dissector and contributed the code back to the team.

In 2006 the project moved house and re-emerged under a new name: Wireshark.

In 2008, after ten years of development, Wireshark finally arrived at version 1.0. This release was the first deemed complete, with the minimum features implemented. Its release coincided with the first Wireshark Developer and User Conference, called Sharkfest.

In 2015 Wireshark 2.0 was released, which featured a new user interface.

1.5. Development and maintenance of Wireshark

Wireshark was initially developed by Gerald Combs. Ongoing development and maintenance of Wireshark is handled by the Wireshark team, a loose group of individuals who fix bugs and provide new functionality.

There have also been a large number of people who have contributed protocol dissectors to Wireshark, and it is expected that this will continue. You can find a list of the people who have contributed code to Wireshark by checking the about dialog box of Wireshark, or at the authors page on the Wireshark web site.

Wireshark is an open source software project, and is released under the GNU General Public License (GPL) version 2. All source code is freely available under the GPL. You are welcome to modify Wireshark to suit your own needs, and it would be appreciated if you contribute your improvements back to the Wireshark team.

You gain three benefits by contributing your improvements back to the community:

  1. Other people who find your contributions useful will appreciate them, and you will know that you have helped people in the same way that the developers of Wireshark have helped people.
  2. The developers of Wireshark might improve your changes even more, as there’s always room for improvement. Or they may implement some advanced things on top of your code, which can be useful for yourself too.
  3. The maintainers and developers of Wireshark will maintain your code as well, fixing it when API changes or other changes are made, and generally keeping it in tune with what is happening with Wireshark. So if Wireshark is updated (which is done often), you can get a new Wireshark version from the website and your changes will already be included without any effort for you.

The Wireshark source code and binary kits for some platforms are all available on the download page of the Wireshark website: https://www.wireshark.org/download.html.

1.6. Reporting problems and getting help

If you have problems or need help with Wireshark there are several places that may be of interest to you (well, besides this guide of course).

1.6.1. Website

You will find lots of useful information on the Wireshark homepage at https://www.wireshark.org/.

1.6.2. Wiki

The Wireshark Wiki at https://wiki.wireshark.org/ provides a wide range of information related to Wireshark and packet capture in general. You will find a lot of information not part of this user’s guide. For example, there is an explanation how to capture on a switched network, an ongoing effort to build a protocol reference and a lot more.

And best of all, if you would like to contribute your knowledge on a specific topic (maybe a network protocol you know well) you can edit the wiki pages by simply using your web browser.

1.6.3. Q&A Site

The Wireshark Q&A site at https://ask.wireshark.org/ offers a resource where questions and answers come together. You have the option to search what questions were asked before and what answers were given by people who knew about the issue. Answers are graded, so you can pick out the best ones easily. If your question hasn’t been discussed before you can post one yourself.

1.6.4. FAQ

The Frequently Asked Questions lists often asked questions and their corresponding answers.

[Note] Read the FAQ

Before sending any mail to the mailing lists below, be sure to read the FAQ. It will often answer any questions you might have. This will save yourself and others a lot of time. Keep in mind that a lot of people are subscribed to the mailing lists.

You will find the FAQ inside Wireshark by clicking the menu item Help/Contents and selecting the FAQ page in the dialog shown.

An online version is available at the Wireshark website at https://www.wireshark.org/faq.html. You might prefer this online version, as it’s typically more up to date and the HTML format is easier to use.

1.6.5. Mailing Lists

There are several mailing lists of specific Wireshark topics available:

wireshark-announce
This mailing list will inform you about new program releases, which usually appear about every 4-8 weeks.
wireshark-users
This list is for users of Wireshark. People post questions about building and using Wireshark, others (hopefully) provide answers.
wireshark-dev
This list is for Wireshark developers. If you want to start developing a protocol dissector, join this list.

You can subscribe to each of these lists from the Wireshark web site: https://www.wireshark.org/lists/. From there, you can choose which mailing list you want to subscribe to by clicking on the Subscribe/Unsubscribe/Options button under the title of the relevant list. The links to the archives are included on that page as well.

[Tip] The lists are archived

You can search in the list archives to see if someone asked the same question some time before and maybe already got an answer. That way you don’t have to wait until someone answers your question.

1.6.6. Reporting Problems

[Note] Note

Before reporting any problems, please make sure you have installed the latest version of Wireshark.

When reporting problems with Wireshark please supply the following information:

  1. The version number of Wireshark and the dependent libraries linked with it, such as Qt or GLib. You can obtain this from Wireshark’s about box or the command wireshark -v.
  2. Information about the platform you run Wireshark on.
  3. A detailed description of your problem.
  4. If you get an error/warning message, copy the text of that message (and also a few lines before and after it, if there are some) so others may find the place where things go wrong. Please don’t give something like: “I get a warning while doing x” as this won’t give a good idea where to look.
[Note] Don’t send large files

Do not send large files (> 1 MB) to the mailing lists. Just place a note that further data is available on request. Large files will only annoy a lot of people on the list who are not interested in your specific problem. If required you will be asked for further data by the persons who really can help you.

[Warning] Don’t send confidential information!

If you send capture files to the mailing lists be sure they don’t contain any sensitive or confidential information like passwords or personally identifiable information (PII).

1.6.7. Reporting Crashes on UNIX/Linux platforms

When reporting crashes with Wireshark it is helpful if you supply the traceback information along with the information mentioned in “Reporting Problems”.

You can obtain this traceback information with the following commands on UNIX or Linux (note the backticks):

$ gdb `whereis wireshark | cut -f2 -d: | cut -d' ' -f2` core >& backtrace.txt
backtrace
^D

If you do not have gdb available, you will have to check out your operating system’s debugger.

Mail backtrace.txt to wireshark-dev[AT]wireshark.org.

1.6.8. Reporting Crashes on Windows platforms

The Windows distributions don’t contain the symbol files (.pdb) because they are very large. You can download them separately at https://www.wireshark.org/download/win32/all-versions/ and https://www.wireshark.org/download/win64/all-versions/ .

Chapter 2. Building and Installing Wireshark

2.1. Introduction

As with all things there must be a beginning and so it is with Wireshark. To use Wireshark you must first install it. If you are running Windows or macOS you can download an official release at https://www.wireshark.org/download.html, install it, and skip the rest of this chapter.

If you are running another operating system such as Linux or FreeBSD you might want to install from source. Several Linux distributions offer Wireshark packages but they commonly ship out-of-date versions. No other versions of UNIX ship Wireshark so far. For that reason, you will need to know where to get the latest version of Wireshark and how to install it.

This chapter shows you how to obtain source and binary packages and how to build Wireshark from source should you choose to do so.

The following are the general steps you would use:

  1. Download the relevant package for your needs, e.g. source or binary distribution.
  2. Compile the source into a binary if needed. This may involve building and/or installing other necessary packages.
  3. Install the binaries into their final destinations.

2.2. Obtaining the source and binary distributions

You can obtain both source and binary distributions from the Wireshark web site: https://www.wireshark.org/download.html. Select the download link and then select the desired binary or source package.

[Note] Download all required files

If you are building Wireshark from source you will In general, unless you have already downloaded Wireshark before, you will most likely need to download several source packages if you are building Wireshark from source. This is covered in more detail below.

Once you have downloaded the relevant files, you can go on to the next step.

2.3. Installing Wireshark under Windows

Windows installer names contain the platform and version. For example, Wireshark-win64-2.9.0.exe installs Wireshark 2.9.0 for 64-bit Windows. The Wireshark installer includes WinPcap which is required for packet capture.

Simply download the Wireshark installer from https://www.wireshark.org/download.html and execute it. Official packages are signed by the Wireshark Foundation. You can choose to install several optional components and select the location of the installed package. The default settings are recommended for most users.

2.3.1. Installation Components

On the Choose Components page of the installer you can select from the following:

  • Wireshark - The network protocol analyzer that we all know and mostly love.
  • TShark - A command-line network protocol analyzer. If you haven’t tried it you should.
  • Plugins & Extensions - Extras for the Wireshark and TShark dissection engines

    • Dissector Plugins - Plugins with some extended dissections.
    • Tree Statistics Plugins - Extended statistics.
    • Mate - Meta Analysis and Tracing Engine - User configurable extension(s) of the display filter engine, see Chapter 12, MATE for details.
    • SNMP MIBs - SNMP MIBs for a more detailed SNMP dissection.
  • Tools - Additional command line tools to work with capture files

    • Editcap - Reads a capture file and writes some or all of the packets into another capture file.
    • Text2Pcap - Reads in an ASCII hex dump and writes the data into a pcap capture file.
    • Reordercap - Reorders a capture file by timestamp.
    • Mergecap - Combines multiple saved capture files into a single output file.
    • Capinfos - Provides information on capture files.
    • Rawshark - Raw packet filter.
  • User’s Guide - Local installation of the User’s Guide. The Help buttons on most dialogs will require an internet connection to show help pages if the User’s Guide is not installed locally.

2.3.2. Additional Tasks

  • Start Menu Shortcuts - Add some start menu shortcuts.
  • Desktop Icon - Add a Wireshark icon to the desktop.
  • Quick Launch Icon - add a Wireshark icon to the Explorer quick launch toolbar.
  • Associate file extensions to Wireshark - Associate standard network trace files to Wireshark.

2.3.3. Install Location

By default Wireshark installs into %ProgramFiles%\Wireshark on 32-bit Windows and %ProgramFiles64%\Wireshark on 64-bit Windows. This expands to C:\Program Files\Wireshark on most systems.

2.3.4. Installing WinPcap

The Wireshark installer contains the latest WinPcap installer.

If you don’t have WinPcap installed you won’t be able to capture live network traffic but you will still be able to open saved capture files. By default the latest version of WinPcap will be installed. If you don’t wish to do this or if you wish to reinstall WinPcap you can check the Install WinPcap box as needed.

For more information about WinPcap see https://www.winpcap.org/ and https://wiki.wireshark.org/WinPcap.

2.3.5. Windows installer command line options

For special cases, there are some command line parameters available:

  • /S runs the installer or uninstaller silently with default values. The silent installer will not install WinPCap.
  • /desktopicon installation of the desktop icon, =yes - force installation, =no - don’t install, otherwise use default settings. This option can be useful for a silent installer.
  • /quicklaunchicon installation of the quick launch icon, =yes - force installation, =no - don’t install, otherwise use default settings.
  • /D sets the default installation directory ($INSTDIR), overriding InstallDir and InstallDirRegKey. It must be the last parameter used in the command line and must not contain any quotes even if the path contains spaces.
  • /NCRC disables the CRC check. We recommend against using this flag.

Example:

> Wireshark-win64-wireshark-2.0.5.exe /NCRC /S /desktopicon=yes /quicklaunchicon=no /D=C:\Program Files\Foo

Running the installer without any parameters shows the normal interactive installer.

2.3.6. Manual WinPcap Installation

As mentioned above, the Wireshark installer takes care of installing WinPcap. The following is only necessary if you want to use a different version than the one included in the Wireshark installer, e.g. because a new WinPcap version was released.

Additional WinPcap versions (including newer alpha or beta releases) can be downloaded from the main WinPcap site at https://www.winpcap.org/. The Installer for Windows supports modern Windows operating systems.

2.3.7. Update Wireshark

By default the offical Windows package will check for new versions and notify you when they are available. If you have the Check for updates preference disabled or if you run Wireshark in an isolated environment you should subcribe to the wireshark-announce mailing list. See Section 1.6.5, “Mailing Lists” for details on subscribing to this list.

New versions of Wireshark are usually released every four to six weeks. Updating Wireshark is done the same way as installing it. Simply download and start the installer exe. A reboot is usually not required and all your personal settings remain unchanged.

2.3.8. Update WinPcap

New versions of WinPcap are less frequently available. You will find WinPcap update instructions the WinPcap web site at https://www.winpcap.org/. You may have to reboot your machine after installing a new WinPcap version.

2.3.9. Uninstall Wireshark

You can uninstall Wireshark using the Programs and Features control panel. Select the “Wireshark” entry to start the uninstallation procedure.

The Wireshark uninstaller provides several options for removal. The default is to remove the core components but keep your personal settings and WinPcap. WinPcap is left installed by default in case other programs need it.

2.3.10. Uninstall WinPcap

You can uninstall WinPcap independently of Wireshark using the WinPcap entry in the Programs and Features control panel. Remember that if you uninstall WinPcap you won’t be able to capture anything with Wireshark.

2.4. Installing Wireshark under macOS

The official macOS packages are distributed as disk images (.dmg) containing the application installer. To install Wireshark simply open the disk image and run the enclosed installer.

The installer package includes Wireshark, its related command line utilities, and a launch daemon that adjusts capture permissions at system startup. See the included Read me first file for more details.

2.5. Building Wireshark from source under UNIX

Building Wireshark requires the proper build environment including a compiler and many supporting libraries. See the Developer’s Guide at https://www.wireshark.org/docs/ for more information.

Use the following general steps to build Wireshark from source under UNIX or Linux:

  1. Unpack the source from its compressed tar file. If you are using Linux or your version of UNIX uses GNU tar you can use the following command:

    $ tar xaf wireshark-2.9.0.tar.xz

    In other cases you will have to use the following commands:

    $ xz -d wireshark-2.9.0.tar.xz
    $ tar xf wireshark-2.9.0.tar
  2. Create a directory to build Wireshark in and change to it.

    $ mkdir build
    $ cd build
  3. Configure your source so it will build correctly for your version of UNIX. You can do this with the following command:

    $ cmake ../wireshark-2.9.0

    If this step fails you will have to look into the logs and rectify the problems, then rerun cmake. Troubleshooting hints are provided in Section 2.7, “Troubleshooting during the build and install on Unix”.

  4. Build the sources.

    $ make

    Once you have build Wireshark with make above, you should be able to run it by entering run/wireshark.

  5. Install the software in its final destination.

    $ make install

Once you have installed Wireshark with make install above, you should be able to run it by entering wireshark.

2.6. Installing the binaries under UNIX

In general installing the binary under your version of UNIX will be specific to the installation methods used with your version of UNIX. For example, under AIX, you would use smit to install the Wireshark binary package, while under Tru64 UNIX (formerly Digital UNIX) you would use setld.

2.6.1. Installing from RPMs under Red Hat and alike

Building RPMs from Wireshark’s source code results in several packages (most distributions follow the same system):

  • The wireshark package contains the core Wireshark libraries and command-line tools.
  • The wireshark or wireshark-qt package contains the Qt-based GUI.

Many distributions use yum or a similar package management tool to make installation of software (including its dependencies) easier. If your distribution uses yum, use the following command to install Wireshark together with the Qt GUI:

yum install wireshark wireshark-qt

If you’ve built your own RPMs from the Wireshark sources you can install them by running, for example:

rpm -ivh wireshark-2.0.0-1.x86_64.rpm wireshark-qt-2.0.0-1.x86_64.rpm

If the above command fails because of missing dependencies, install the dependencies first, and then retry the step above.

2.6.2. Installing from debs under Debian, Ubuntu and other Debian derivatives

If you can just install from the repository then use

$ aptitude install wireshark

Aptitude should take care of all of the dependency issues for you.

Use the following command to install downloaded Wireshark debs under Debian:

$ dpkg -i wireshark-common_2.0.5.0-1_i386.deb wireshark_wireshark-2.0.5.0-1_i386.deb

dpkg doesn’t take care of all dependencies, but reports what’s missing.

[Note] Capturing requires privileges

By installing Wireshark packages non-root users won’t gain rights automatically to capture packets. To allow non-root users to capture packets follow the procedure described in /usr/share/doc/wireshark-common/README.Debian

2.6.3. Installing from portage under Gentoo Linux

Use the following command to install Wireshark under Gentoo Linux with all of the extra features:

$ USE="c-ares ipv6 snmp ssl kerberos threads selinux" emerge wireshark

2.6.4. Installing from packages under FreeBSD

Use the following command to install Wireshark under FreeBSD:

$ pkg_add -r wireshark

pkg_add should take care of all of the dependency issues for you.

2.7. Troubleshooting during the build and install on Unix

A number of errors can occur during the build and installation process. Some hints on solving these are provided here.

If the cmake stage fails you will need to find out why. You can check the file CMakeOutput.log and CMakeError.log in the build directory to find out what failed. The last few lines of this file should help in determining the problem.

The standard problems are that you do not have a required development package on your system or that the development package isn’t new enough. Note that installing a library package isn’t enough. You need to install its development package as well. cmake will also fail if you do not have libpcap (at least the required include files) on your system.

If you cannot determine what the problems are, send an email to the wireshark-dev mailing list explaining your problem. Include the output from cmake and anything else you think is relevant such as a trace of the make stage.

2.8. Building from source under Windows

We strongly recommended that you use the binary installer for Windows unless you want to start developing Wireshark on the Windows platform.

For further information how to build Wireshark for Windows from the sources see the Developer’s Guide at https://www.wireshark.org/docs/.

You may also want to have a look at the Development Wiki (https://wiki.wireshark.org/Development) for the latest available development documentation.

Chapter 3. User Interface

3.1. Introduction

By now you have installed Wireshark and are most likely keen to get started capturing your first packets. In the next chapters we will explore:

  • How the Wireshark user interface works
  • How to capture packets in Wireshark
  • How to view packets in Wireshark
  • How to filter packets in Wireshark
  • …​ and many other things!

3.2. Start Wireshark

You can start Wireshark from your shell or window manager.

[Tip] Power user tip

When starting Wireshark it’s possible to specify optional settings using the command line. See Section 11.2, “Start Wireshark from the command line” for details.

In the following chapters a lot of screenshots from Wireshark will be shown. As Wireshark runs on many different platforms with many different window managers, different styles applied and there are different versions of the underlying GUI toolkit used, your screen might look different from the provided screenshots. But as there are no real differences in functionality these screenshots should still be well understandable.

3.3. The Main window

Let’s look at Wireshark’s user interface. Figure 3.1, “The Main window” shows Wireshark as you would usually see it after some packets are captured or loaded (how to do this will be described later).

Figure 3.1. The Main window

ws main

Wireshark’s main window consists of parts that are commonly known from many other GUI programs.

  1. The menu (see Section 3.4, “The Menu”) is used to start actions.
  2. The main toolbar (see Section 3.15, “The “Main” Toolbar”) provides quick access to frequently used items from the menu.
  3. The filter toolbar (see Section 3.16, “The “Filter” Toolbar”) provides a way to directly manipulate the currently used display filter (see Section 6.3, “Filtering packets while viewing”).
  4. The packet list pane (see Section 3.17, “The “Packet List” Pane”) displays a summary of each packet captured. By clicking on packets in this pane you control what is displayed in the other two panes.
  5. The packet details pane (see Section 3.18, “The “Packet Details” Pane”) displays the packet selected in the packet list pane in more detail.
  6. The packet bytes pane (see Section 3.19, “The “Packet Bytes” Pane”) displays the data from the packet selected in the packet list pane, and highlights the field selected in the packet details pane.
  7. The statusbar (see Section 3.20, “The Statusbar”) shows some detailed information about the current program state and the captured data.
[Tip] Tip

The layout of the main window can be customized by changing preference settings. See Section 11.5, “Preferences” for details!

3.3.1. Main Window Navigation

Packet list and detail navigation can be done entirely from the keyboard. Table 3.1, “Keyboard Navigation” shows a list of keystrokes that will let you quickly move around a capture file. See Table 3.6, “Go menu items” for additional navigation keystrokes.

Table 3.1. Keyboard Navigation

Accelerator Description

Tab or Shift+Tab

Move between screen elements, e.g. from the toolbars to the packet list to the packet detail.

Move to the next packet or detail item.

Move to the previous packet or detail item.

Ctrl+ or F8

Move to the next packet, even if the packet list isn’t focused.

Ctrl+ or F7

Move to the previous packet, even if the packet list isn’t focused.

Ctrl+.

Move to the next packet of the conversation (TCP, UDP or IP).

Ctrl+,

Move to the previous packet of the conversation (TCP, UDP or IP).

Alt+ or Option+ (macOS)

Move to the next packet in the selection history.

Alt+ or Option+ (macOS)

Move to the previous packet in the selection history.

In the packet detail, closes the selected tree item. If it’s already closed, jumps to the parent node.

In the packet detail, opens the selected tree item.

Shift+

In the packet detail, opens the selected tree item and all of its subtrees.

Ctrl+

In the packet detail, opens all tree items.

Ctrl+

In the packet detail, closes all tree items.

Backspace

In the packet detail, jumps to the parent node.

Return or Enter

In the packet detail, toggles the selected tree item.


HelpAbout WiresharkKeyboard Shortcuts will show a list of all shortcuts in the main window. Additionally, typing anywhere in the main window will start filling in a display filter.

3.4. The Menu

Wireshark’s main menu is located either at the top of the main window (Windows, Linux) or at the top of your main screen (macOS). An example is shown in Figure 3.2, “The Menu”.

[Note] Note

Some menu items will be disabled (greyed out) if the corresponding feature isn’t available. For example, you cannot save a capture file if you haven’t captured or loaded any packets.

Figure 3.2. The Menu

ws menu

The main menu contains the following items:

File
This menu contains items to open and merge capture files, save, print, or export capture files in whole or in part, and to quit the Wireshark application. See Section 3.5, “The “File” menu”.
Edit
This menu contains items to find a packet, time reference or mark one or more packets, handle configuration profiles, and set your preferences; (cut, copy, and paste are not presently implemented). See Section 3.6, “The “Edit” Menu”.
View
This menu controls the display of the captured data, including colorization of packets, zooming the font, showing a packet in a separate window, expanding and collapsing trees in packet details, …​. See Section 3.7, “The “View” Menu”.
Go
This menu contains items to go to a specific packet. See Section 3.8, “The “Go” Menu”.
Capture
This menu allows you to start and stop captures and to edit capture filters. See Section 3.9, “The “Capture” menu”.
Analyze
This menu contains items to manipulate display filters, enable or disable the dissection of protocols, configure user specified decodes and follow a TCP stream. See Section 3.10, “The “Analyze” Menu”.
Statistics
This menu contains items to display various statistic windows, including a summary of the packets that have been captured, display protocol hierarchy statistics and much more. See Section 3.11, “The “Statistics” Menu”.
Telephony
This menu contains items to display various telephony related statistic windows, including a media analysis, flow diagrams, display protocol hierarchy statistics and much more. See Section 3.12, “The “Telephony” Menu”.
Wireless
The items in this menu show Bluetooth and IEEE 802.11 wireless statistics.
Tools
This menu contains various tools available in Wireshark, such as creating Firewall ACL Rules. See Section 3.13, “The “Tools” Menu”.
Help
This menu contains items to help the user, e.g. access to some basic help, manual pages of the various command line tools, online access to some of the webpages, and the usual about dialog. See Section 3.14, “The “Help” Menu”.

Each of these menu items is described in more detail in the sections that follow.

[Tip] Shortcuts make life easier

Most common menu items have keyboard shortcuts. For example, you can press the Control (or Strg in German) and the K keys together to open the “Capture Options” dialog.

3.5. The “File” menu

The Wireshark file menu contains the fields shown in Table 3.2, “File menu items”.

Figure 3.3. The “File” Menu

ws file menu

Table 3.2. File menu items

Menu Item Accelerator Description

Open…​

Ctrl+O

This shows the file open dialog box that allows you to load a capture file for viewing. It is discussed in more detail in Section 5.2.1, “The “Open Capture File” dialog box”.

Open Recent

 

This lets you open recently opened capture files. Clicking on one of the submenu items will open the corresponding capture file directly.

Merge…​

 

This menu item lets you merge a capture file into the currently loaded one. It is discussed in more detail in Section 5.4, “Merging capture files”.

Import from Hex Dump…​

 

This menu item brings up the import file dialog box that allows you to import a text file containing a hex dump into a new temporary capture. It is discussed in more detail in Section 5.5, “Import hex dump”.

Close

Ctrl+W

This menu item closes the current capture. If you haven’t saved the capture, you will be asked to do so first (this can be disabled by a preference setting).

Save

Ctrl+S

This menu item saves the current capture. If you have not set a default capture file name (perhaps with the -w <capfile> option), Wireshark pops up the Save Capture File As dialog box (which is discussed further in Section 5.3.1, “The “Save Capture File As” dialog box”).

If you have already saved the current capture, this menu item will be greyed out.

You cannot save a live capture while the capture is in progress. You must stop the capture in order to save.

Save As…​

Shift+Ctrl+S

This menu item allows you to save the current capture file to whatever file you would like. It pops up the Save Capture File As dialog box (which is discussed further in Section 5.3.1, “The “Save Capture File As” dialog box”).

File SetList Files

 

This menu item allows you to show a list of files in a file set. It pops up the Wireshark List File Set dialog box (which is discussed further in Section 5.6, “File Sets”).

File SetNext File

 

If the currently loaded file is part of a file set, jump to the next file in the set. If it isn’t part of a file set or just the last file in that set, this item is greyed out.

File SetPrevious File

 

If the currently loaded file is part of a file set, jump to the previous file in the set. If it isn’t part of a file set or just the first file in that set, this item is greyed out.

Export Specified Packets…​

 

This menu item allows you to export all (or some) of the packets in the capture file to file. It pops up the Wireshark Export dialog box (which is discussed further in Section 5.7, “Exporting data”).

Export Packet Dissections…​

Ctrl+H

These menu items allow you to export the currently selected bytes in the packet bytes pane to a text file file in a number of formats including plain, CSV, and XML. It is discussed further in Section 5.7.7, “The “Export selected packet bytes” dialog box”.

Export Objects

 

These menu items allow you to export captured DICOM, HTTP, IMF, SMB, or TFTP objects into local files. It pops up a corresponding object list (which is discussed further in Section 5.7.8, “The “Export Objects” dialog box”)

Print…​

Ctrl+P

This menu item allows you to print all (or some) of the packets in the capture file. It pops up the Wireshark Print dialog box (which is discussed further in Section 5.8, “Printing packets”).

Quit

Ctrl+Q

This menu item allows you to quit from Wireshark. Wireshark will ask to save your capture file if you haven’t previously saved it (this can be disabled by a preference setting).


3.6. The “Edit” Menu

The Wireshark Edit menu contains the fields shown in Table 3.3, “Edit menu items”.

Figure 3.4. The “Edit” Menu

ws edit menu

Table 3.3. Edit menu items

Menu Item Accelerator Description

Copy

 

These menu items will copy the packet list, packet detail, or properties of the currently selected packet to the clipboard.

Find Packet…​

Ctrl+F

This menu item brings up a toolbar that allows you to find a packet by many criteria. There is further information on finding packets in Section 6.8, “Finding packets”.

Find Next

Ctrl+N

This menu item tries to find the next packet matching the settings from “Find Packet…​”.

Find Previous

Ctrl+B

This menu item tries to find the previous packet matching the settings from “Find Packet…​”.

Mark/Unmark Packet

Ctrl+M

This menu item marks the currently selected packet. See Section 6.10, “Marking packets” for details.

Mark All Displayed Packets

Shift+Ctrl+M

This menu item marks all displayed packets.

Unmark All Displayed Packets

Ctrl+Alt+M

This menu item unmarks all displayed packets.

Next Mark

Shift+Alt+N

Find the next marked packet.

Previous Mark

Shift+Alt+B

Find the previous marked packet.

Ignore/Unignore Packet

Ctrl+D

This menu item marks the currently selected packet as ignored. See Section 6.11, “Ignoring packets” for details.

Ignore All Displayed

Shift+Ctrl+D

This menu item marks all displayed packets as ignored.

Unignore All Displayed

Ctrl+Alt+D

This menu item unmarks all ignored packets.

Set/Unset Time Reference

Ctrl+T

This menu item set a time reference on the currently selected packet. See Section 6.12.1, “Packet time referencing” for more information about the time referenced packets.

Unset All Time References

Ctrl+Alt+T

This menu item removes all time references on the packets.

Next Time Reference

Ctrl+Alt+N

This menu item tries to find the next time referenced packet.

Previous Time Reference

Ctrl+Alt+B

This menu item tries to find the previous time referenced packet.

Time Shift

Ctrl+Shift+T

This will show the Time Shift dialog, which allows you to adjust the timestamps of some or all packets.

Packet Comment…​

 

This will let you add a comment to a single packet. Note that the ability to save packet comments depends on your file format. E.g. pcapng supports comments, pcap does not.

Capture Comment…​

 

This will let you add a capture comment. Note that the ability to save capture comments depends on your file format. E.g. pcapng supports comments, pcap does not.

Configuration Profiles…​

Shift+Ctrl+A

This menu item brings up a dialog box for handling configuration profiles. More detail is provided in Section 11.6, “Configuration Profiles”.

Preferences…​

Shift+Ctrl+P or Cmd+, (macOS)

This menu item brings up a dialog box that allows you to set preferences for many parameters that control Wireshark. You can also save your preferences so Wireshark will use them the next time you start it. More detail is provided in Section 11.5, “Preferences”.


3.7. The “View” Menu

The Wireshark View menu contains the fields shown in Table 3.4, “View menu items”.

Figure 3.5. The “View” Menu

ws view menu

Table 3.4. View menu items

Menu Item Accelerator Description

Main Toolbar

 

This menu item hides or shows the main toolbar, see Section 3.15, “The “Main” Toolbar”.

Filter Toolbar

 

This menu item hides or shows the filter toolbar, see Section 3.16, “The “Filter” Toolbar”.

Wireless Toolbar

 

This menu item hides or shows the wireless toolbar. May not be present on some platforms.

Statusbar

 

This menu item hides or shows the statusbar, see Section 3.20, “The Statusbar”.

Packet List

 

This menu item hides or shows the packet list pane, see Section 3.17, “The “Packet List” Pane”.

Packet Details

 

This menu item hides or shows the packet details pane, see Section 3.18, “The “Packet Details” Pane”.

Packet Bytes

 

This menu item hides or shows the packet bytes pane, see Section 3.19, “The “Packet Bytes” Pane”.

Time Display FormatDate and Time of Day: 1970-01-01 01:02:03.123456

 

Selecting this tells Wireshark to display the time stamps in date and time of day format, see Section 6.12, “Time display formats and time references”.

The fields “Time of Day”, “Date and Time of Day”, “Seconds Since Beginning of Capture”, “Seconds Since Previous Captured Packet” and “Seconds Since Previous Displayed Packet” are mutually exclusive.

Time Display FormatTime of Day: 01:02:03.123456

 

Selecting this tells Wireshark to display time stamps in time of day format, see Section 6.12, “Time display formats and time references”.

Time Display FormatSeconds Since Epoch (1970-01-01): 1234567890.123456

 

Selecting this tells Wireshark to display time stamps in seconds since 1970-01-01 00:00:00, see Section 6.12, “Time display formats and time references”.

Time Display FormatSeconds Since Beginning of Capture: 123.123456

 

Selecting this tells Wireshark to display time stamps in seconds since beginning of capture format, see Section 6.12, “Time display formats and time references”.

Time Display FormatSeconds Since Previous Captured Packet: 1.123456

 

Selecting this tells Wireshark to display time stamps in seconds since previous captured packet format, see Section 6.12, “Time display formats and time references”.

Time Display FormatSeconds Since Previous Displayed Packet: 1.123456

 

Selecting this tells Wireshark to display time stamps in seconds since previous displayed packet format, see Section 6.12, “Time display formats and time references”.

Time Display FormatAutomatic (File Format Precision)

 

Selecting this tells Wireshark to display time stamps with the precision given by the capture file format used, see Section 6.12, “Time display formats and time references”.

The fields “Automatic”, “Seconds” and “…​seconds” are mutually exclusive.

Time Display FormatSeconds: 0

 

Selecting this tells Wireshark to display time stamps with a precision of one second, see Section 6.12, “Time display formats and time references”.

Time Display Format…​seconds: 0…​.

 

Selecting this tells Wireshark to display time stamps with a precision of one second, decisecond, centisecond, millisecond, microsecond or nanosecond, see Section 6.12, “Time display formats and time references”.

Time Display FormatDisplay Seconds with hours and minutes

 

Selecting this tells Wireshark to display time stamps in seconds, with hours and minutes.

Name ResolutionResolve Name

 

This item allows you to trigger a name resolve of the current packet only, see Section 7.9, “Name Resolution”.

Name ResolutionEnable for MAC Layer

 

This item allows you to control whether or not Wireshark translates MAC addresses into names, see Section 7.9, “Name Resolution”.

Name ResolutionEnable for Network Layer

 

This item allows you to control whether or not Wireshark translates network addresses into names, see Section 7.9, “Name Resolution”.

Name ResolutionEnable for Transport Layer

 

This item allows you to control whether or not Wireshark translates transport addresses into names, see Section 7.9, “Name Resolution”.

Colorize Packet List

 

This item allows you to control whether or not Wireshark should colorize the packet list.

Enabling colorization will slow down the display of new packets while capturing / loading capture files.

Auto Scroll in Live Capture

 

This item allows you to specify that Wireshark should scroll the packet list pane as new packets come in, so you are always looking at the last packet. If you do not specify this, Wireshark simply adds new packets onto the end of the list, but does not scroll the packet list pane.

Zoom In

Ctrl++

Zoom into the packet data (increase the font size).

Zoom Out

Ctrl+-

Zoom out of the packet data (decrease the font size).

Normal Size

Ctrl+=

Set zoom level back to 100% (set font size back to normal).

Resize All Columns

Shift+Ctrl+R

Resize all column widths so the content will fit into it.

Resizing may take a significant amount of time, especially if a large capture file is loaded.

Displayed Columns

 

This menu items folds out with a list of all configured columns. These columns can now be shown or hidden in the packet list.

Expand Subtrees

Shift+

This menu item expands the currently selected subtree in the packet details tree.

Collapse Subtrees

Shift+

This menu item collapses the currently selected subtree in the packet details tree.

Expand All

Ctrl+

Wireshark keeps a list of all the protocol subtrees that are expanded, and uses it to ensure that the correct subtrees are expanded when you display a packet. This menu item expands all subtrees in all packets in the capture.

Collapse All

Ctrl+

This menu item collapses the tree view of all packets in the capture list.

Colorize Conversation

 

This menu item brings up a submenu that allows you to color packets in the packet list pane based on the addresses of the currently selected packet. This makes it easy to distinguish packets belonging to different conversations. Section 11.3, “Packet colorization”.

Colorize ConversationColor 1-10

 

These menu items enable one of the ten temporary color filters based on the currently selected conversation.

Colorize ConversationReset coloring

 

This menu item clears all temporary coloring rules.

Colorize ConversationNew Coloring Rule…​

 

This menu item opens a dialog window in which a new permanent coloring rule can be created based on the currently selected conversation.

Coloring Rules…​

 

This menu item brings up a dialog box that allows you to color packets in the packet list pane according to filter expressions you choose. It can be very useful for spotting certain types of packets, see Section 11.3, “Packet colorization”.

Internals

 

Information about various internal data structures. See Table 3.5, “Internals menu items” below for more information.

Show Packet in New Window

 

This menu item brings up the selected packet in a separate window. The separate window shows only the tree view and byte view panes.

Reload

Ctrl+R

This menu item allows you to reload the current capture file.


Table 3.5. Internals menu items

Menu Item Description

Conversation Hash Tables

Shows the tuples (address and port combinations) used to identify each conversation.

Dissector Tables

Shows tables of subdissector relationships.

Supported Protocols

Displays supported protocols and protocol fields.


3.8. The “Go” Menu

The Wireshark Go menu contains the fields shown in Table 3.6, “Go menu items”.

Figure 3.6. The “Go” Menu

ws go menu

Table 3.6. Go menu items

Menu Item Accelerator Description

Back

Alt+

Jump to the recently visited packet in the packet history, much like the page history in a web browser.

Forward

Alt+

Jump to the next visited packet in the packet history, much like the page history in a web browser.

Go to Packet…​

Ctrl+G

Bring up a window frame that allows you to specify a packet number, and then goes to that packet. See Section 6.9, “Go to a specific packet” for details.

Go to Corresponding Packet

 

Go to the corresponding packet of the currently selected protocol field. If the selected field doesn’t correspond to a packet, this item is greyed out.

Previous Packet

Ctrl+

Move to the previous packet in the list. This can be used to move to the previous packet even if the packet list doesn’t have keyboard focus.

Next Packet

Ctrl+

Move to the next packet in the list. This can be used to move to the previous packet even if the packet list doesn’t have keyboard focus.

First Packet

Ctrl+Home

Jump to the first packet of the capture file.

Last Packet

Ctrl+End

Jump to the last packet of the capture file.

Previous Packet In Conversation

Ctrl+,

Move to the previous packet in the current conversation. This can be used to move to the previous packet even if the packet list doesn’t have keyboard focus.

Next Packet In Conversation

Ctrl+.

Move to the next packet in the current conversation. This can be used to move to the previous packet even if the packet list doesn’t have keyboard focus.


3.9. The “Capture” menu

The Wireshark Capture menu contains the fields shown in Table 3.7, “Capture menu items”.

Figure 3.7. The “Capture” Menu

ws capture menu

Table 3.7. Capture menu items

Menu Item Accelerator Description

Interfaces…​

Ctrl+I

This menu item brings up a dialog box that shows what’s going on at the network interfaces Wireshark knows of, see Section 4.4, “The “Capture Interfaces” dialog box”) .

Options…​

Ctrl+K

This menu item brings up the Capture Options dialog box (discussed further in Section 4.5, “The “Capture Options” dialog box”) and allows you to start capturing packets.

Start

Ctrl+E

Immediately start capturing packets with the same settings than the last time.

Stop

Ctrl+E

This menu item stops the currently running capture, see Section 4.14.1, “Stop the running capture”) .

Restart

Ctrl+R

This menu item stops the currently running capture and starts again with the same options, this is just for convenience.

Capture Filters…​

 

This menu item brings up a dialog box that allows you to create and edit capture filters. You can name filters, and you can save them for future use. More detail on this subject is provided in Section 6.6, “Defining and saving filters”


3.10. The “Analyze” Menu

The Wireshark Analyze menu contains the fields shown in Table 3.8, “Analyze menu items”.

Figure 3.8. The “Analyze” Menu

ws analyze menu

Table 3.8. Analyze menu items

Menu Item Accelerator Description

Display Filters…​

 

This menu item brings up a dialog box that allows you to create and edit display filters. You can name filters, and you can save them for future use. More detail on this subject is provided in Section 6.6, “Defining and saving filters”

Display Filter Macros…​

 

This menu item brings up a dialog box that allows you to create and edit display filter macros. You can name filter macros, and you can save them for future use. More detail on this subject is provided in Section 6.7, “Defining and saving filter macros”

Apply as Column

 

This menu item adds the selected protocol item in the packet details pane as a column to the packet list.

Apply as Filter…​

 

These menu items will change the current display filter and apply the changed filter immediately. Depending on the chosen menu item, the current display filter string will be replaced or appended to by the selected protocol field in the packet details pane.

Prepare a Filter…​

 

These menu items will change the current display filter but won’t apply the changed filter. Depending on the chosen menu item, the current display filter string will be replaced or appended to by the selected protocol field in the packet details pane.

Enabled Protocols…​

Shift+Ctrl+E

This menu item allows the user to enable/disable protocol dissectors, see Section 11.4.1, “The “Enabled Protocols” dialog box”

Decode As…​

 

This menu item allows the user to force Wireshark to decode certain packets as a particular protocol, see Section 11.4.2, “User Specified Decodes”

User Specified Decodes…​

 

This menu item allows the user to force Wireshark to decode certain packets as a particular protocol, see Section 11.4.3, “Show User Specified Decodes”

FollowTCP Stream

 

This menu item brings up a separate window and displays all the TCP segments captured that are on the same TCP connection as a selected packet, see Section 7.2, “Following Protocol Streams”

FollowUDP Stream

 

Same functionality as “Follow TCP Stream” but for UDP streams.

FollowTLS Stream

 

Same functionality as “Follow TCP Stream” but for TLS or SSL streams. See the wiki page on SSL for instructions on providing TLS keys.

FollowHTTP Stream

 

Same functionality as “Follow TCP Stream” but for HTTP streams.

Expert Info

 

Open a dialog showing some expert information about the captured packets. The amount of information will depend on the protocol and varies from very detailed to non-existent. XXX - add a new section about this and link from here

Conversation Filter…​

 

In this menu you will find conversation filter for various protocols.


3.11. The “Statistics” Menu

The Wireshark Statistics menu contains the fields shown in Table 3.9, “Statistics menu items”.

Figure 3.9. The “Statistics” Menu

ws statistics menu

All menu items will bring up a new window showing specific statistical information.

Table 3.9. Statistics menu items

Menu Item Accelerator Description

Capture File Properties

 

Show information about the capture file, see Section 8.2, “The “Capture File Properties” Window”.

Resolved Addresses

 

See Section 8.3, “Resolved Addresses”

Protocol Hierarchy

 

Display a hierarchical tree of protocol statistics, see Section 8.4, “The “Protocol Hierarchy” Window”.

Conversations

 

Display a list of conversations (traffic between two endpoints), see Section 8.5.1, “The “Conversations” Window”.

Endpoints

 

Display a list of endpoints (traffic to/from an address), see Section 8.6.1, “The “Endpoints” Window”.

Packet Lengths

 

See Section 8.7, “Packet Lengths”

IO Graphs

 

Display user specified graphs (e.g. the number of packets in the course of time), see Section 8.8, “The “I/O Graph” Window”.

Service Response Time

 

Display the time between a request and the corresponding response, see Section 8.9, “Service Response Time”.

DHCP (BOOTP)

 

See Section 8.10, “DHCP (BOOTP) Statistics”

ONC-RPC Programs

 

See Section 8.11, “ONC-RPC Programs”

29West

 

See Section 8.12, “29West”

ANCP

 

See Section 8.13, “ANCP”

BACnet

 

See Section 8.14, “BACnet”

Collectd

 

See Section 8.15, “Collectd”

DNS

 

See Section 8.16, “DNS”

Flow Graph

 

See Section 8.17, “Flow Graph”

HART-IP

 

See Section 8.18, “HART-IP”

HPFEEDS

 

See Section 8.19, “HPFEEDS”

HTTP

 

HTTP request/response statistics, see Section 8.20, “HTTP Statistics”

HTTP2

 

See Section 8.21, “HTTP2”

Sametime

 

See Section 8.22, “Sametime”

TCP Stream Graphs

 

See Section 8.23, “TCP Stream Graphs”

UDP Multicast Streams

 

See Section 8.24, “UDP Multicast Graphs”

F5

 

See Section 8.25, “F5”

IPv4 Statistics

 

See Section 8.26, “IPv4 Statistics”

IPv6 Statistics

 

See Section 8.27, “IPv6 Statistics”


3.12. The “Telephony” Menu

The Wireshark Telephony menu contains the fields shown in Table 3.10, “Telephony menu items”.

Figure 3.10. The “Telephony” Menu

ws telephony menu

All menu items will bring up a new window showing specific telephony related statistical information.

Table 3.10. Telephony menu items

Menu Item Accelerator Description

VoIP Calls…​

 

See Section 9.2, “VoIP Calls”

ANSI

 

See Section 9.3, “ANSI”

GSM

 

See Section 9.4, “GSM”

IAX2 Stream Analysis

 

See Section 9.5, “IAX2 Stream Analysis”

ISUP Messages

 

See Section 9.6, “ISUP Messages”

LTE

 

See Section 9.7, “LTE”

MTP3

 

See Section 9.8, “MTP3”

Osmux

 

See Section 9.9, “Osmux”

RTP

 

See Section 9.10, “RTP Analysis”

RTSP

 

See Section 9.11, “RTSP”

SCTP

 

See Section 9.12, “SCTP”

SMPP Operations

 

See Section 9.13, “SMPP Operations”

UCP Messages

 

See Section 9.14, “UCP Messages”

H.225

 

See Section 9.15, “H.225”

SIP Flows

 

See Section 9.16, “SIP Flows”

SIP Statistics

 

See Section 9.17, “SIP Statistics”

WAP-WSP Packet Counter

 

See Section 9.18, “WAP-WSP Packet Counter”


3.13. The “Tools” Menu

The Wireshark Tools menu contains the fields shown in Table 3.11, “Tools menu items”.

Figure 3.11. The “Tools” Menu

ws tools menu

Table 3.11. Tools menu items

Menu Item Accelerator Description

Firewall ACL Rules

 

This allows you to create command-line ACL rules for many different firewall products, including Cisco IOS, Linux Netfilter (iptables), OpenBSD pf and Windows Firewall (via netsh). Rules for MAC addresses, IPv4 addresses, TCP and UDP ports, and IPv4+port combinations are supported.

It is assumed that the rules will be applied to an outside interface.

Lua

 

These options allow you to work with the Lua interpreter optionally build into Wireshark. See the “Lua Support in Wireshark” in the Wireshark Developer’s Guide.


3.14. The “Help” Menu

The Wireshark Help menu contains the fields shown in Table 3.12, “Help menu items”.

Figure 3.12. The “Help” Menu

ws help menu

Table 3.12. Help menu items

Menu Item Accelerator Description

Contents

F1

This menu item brings up a basic help system.

Manual Pages…​

 

This menu item starts a Web browser showing one of the locally installed html manual pages.

Website

 

This menu item starts a Web browser showing the webpage from: https://www.wireshark.org/.

FAQs

 

This menu item starts a Web browser showing various FAQs.

Downloads

 

This menu item starts a Web browser showing the downloads from: https://www.wireshark.org/download.html.

Wiki

 

This menu item starts a Web browser showing the front page from: https://wiki.wireshark.org/.

Sample Captures

 

This menu item starts a Web browser showing the sample captures from: https://wiki.wireshark.org/SampleCaptures.

About Wireshark

 

This menu item brings up an information window that provides various detailed information items on Wireshark, such as how it’s built, the plugins loaded, the used folders, …​


[Note] Note

Opening a Web browser might be unsupported in your version of Wireshark. If this is the case the corresponding menu items will be hidden.

If calling a Web browser fails on your machine, nothing happens, or the browser starts but no page is shown, have a look at the web browser setting in the preferences dialog.

3.15. The “Main” Toolbar

The main toolbar provides provides quick access to frequently used items from the menu. This toolbar cannot be customized by the user, but it can be hidden using the View menu if the space on the screen is needed to show more packet data.

Items in the toolbar will be enabled or disabled (greyed out) similar to their corresponding menu items. For example, in the image below shows the main window toolbar after a file has been opened. Various file-related buttons are enabled, but the stop capture button is disabled because a capture is not in progress.

Figure 3.13. The “Main” toolbar

ws main toolbar

Table 3.13. Main toolbar items

Toolbar Icon Toolbar Item Menu Item Description

x capture start

Start

CaptureStart

Starts capturing packets with the same options as the last capture or the default options if none were set (Section 4.3, “Start Capturing”).

x capture stop

Stop

CaptureStop

Stops the currently running capture (Section 4.3, “Start Capturing”).

x capture restart

Restart

CaptureRestart

Restarts the current capture session.

x capture options

Options…​

CaptureOptions…​

Opens the “Capture Options” dialog box. See Section 4.3, “Start Capturing” for details.

document open

Open…​

FileOpen…​

Opens the file open dialog box, which allows you to load a capture file for viewing. It is discussed in more detail in Section 5.2.1, “The “Open Capture File” dialog box”.

x capture file save

Save As…​

FileSave As…​

Save the current capture file to whatever file you would like. See Section 5.3.1, “The “Save Capture File As” dialog box” for details. If you currently have a temporary capture file open the “Save” icon will be shown instead.

x capture file close

Close

FileClose

Closes the current capture. If you have not saved the capture, you will be asked to save it first.

x capture file reload

Reload

ViewReload

Reloads the current capture file.

edit find

Find Packet…​

EditFind Packet…​

Find a packet based on different criteria. See Section 6.8, “Finding packets” for details.

go previous

Go Back

GoGo Back

Jump back in the packet history. Hold down the Alt key (Option on macOS) to go back in the selection history.

go next

Go Forward

GoGo Forward

Jump forward in the packet history. Hold down the Alt key (Option on macOS) to go forward in the selection history.

go jump

Go to Packet…​

GoGo to Packet…​

Go to a specific packet.

go first

Go To First Packet

GoFirst Packet

Jump to the first packet of the capture file.

go last

Go To Last Packet

GoLast Packet

Jump to the last packet of the capture file.

x stay last

Auto Scroll in Live Capture

ViewAuto Scroll in Live Capture

Auto scroll packet list while doing a live capture (or not).

x colorize packets

Colorize

ViewColorize

Colorize the packet list (or not).

zoom in

Zoom In

ViewZoom In

Zoom into the packet data (increase the font size).

zoom out

Zoom Out

ViewZoom Out

Zoom out of the packet data (decrease the font size).

zoom original

Normal Size

ViewNormal Size

Set zoom level back to 100%.

x resize columns

Resize Columns

ViewResize Columns

Resize columns, so the content fits into them.


3.16. The “Filter” Toolbar

The filter toolbar lets you quickly edit and apply display filters. More information on display filters is available in Section 6.3, “Filtering packets while viewing”.

Figure 3.14. The “Filter” toolbar

ws filter toolbar

Table 3.14. Filter toolbar items

Toolbar Icon Name Description

filter toolbar bookmark

Bookmarks

Manage or select saved filters.

filter toolbar input

Filter Input

The area to enter or edit a display filter string, see Section 6.4, “Building display filter expressions”. A syntax check of your filter string is done while you are typing. The background will turn red if you enter an incomplete or invalid string, and will become green when you enter a valid string.

After you’ve changed something in this field, don’t forget to press the Apply button (or the Enter/Return key), to apply this filter string to the display.

This field is also where the current applied filter is displayed.

filter toolbar clear

Clear

Reset the current display filter and clear the edit area.

filter toolbar apply

Apply

Apply the current value in the edit area as the new display filter.

Applying a display filter on large capture files might take quite a long time.

filter toolbar recent

Recent

Select from a list of recently applied filters.

Expression…​

Filter Expression

Open a dialog box that lets you edit a display filter from a list of protocol fields as described in Section 6.5, “The “Filter Expression” dialog box”

filter toolbar add

Add Button

Add a new filter expression button.

Squirrels

Expression Button

Example filter expression button named “Squirrels”.


3.17. The “Packet List” Pane

The packet list pane displays all the packets in the current capture file.

Figure 3.15. The “Packet List” pane

ws list pane

Each line in the packet list corresponds to one packet in the capture file. If you select a line in this pane, more details will be displayed in the “Packet Details” and “Packet Bytes” panes.

While dissecting a packet, Wireshark will place information from the protocol dissectors into the columns. As higher level protocols might overwrite information from lower levels, you will typically see the information from the highest possible level only.

For example, let’s look at a packet containing TCP inside IP inside an Ethernet packet. The Ethernet dissector will write its data (such as the Ethernet addresses), the IP dissector will overwrite this by its own (such as the IP addresses), the TCP dissector will overwrite the IP information, and so on.

There are a lot of different columns available. Which columns are displayed can be selected by preference settings, see Section 11.5, “Preferences”.

The default columns will show:

  • No. The number of the packet in the capture file. This number won’t change, even if a display filter is used.
  • Time The timestamp of the packet. The presentation format of this timestamp can be changed, see Section 6.12, “Time display formats and time references”.
  • Source The address where this packet is coming from.
  • Destination The address where this packet is going to.
  • Protocol The protocol name in a short (perhaps abbreviated) version.
  • Length The length of each packet.
  • Info Additional information about the packet content.

The first column shows how each packet is related to the selected packet. For example, in the image above the first packet is selected, which is a DNS request. Wireshark shows a rightward arrow for the request itself, followed by a leftward arrow for the response in packet 2. Why is there a dashed line? There are more DNS packets further down that use the same port numbers. Wireshark treats them as belonging to the same conversation and draws a line connecting them.

Table 3.15. Related packet symbols

related first

First packet in a conversation.

related current

Part of the selected conversation.

related other

Not part of the selected conversation.

related last

Last packet in a conversation.

related request

Request.

related response

Response.

related ack

The selected packet acknowledges this packet.

related dup ack

The selected packet is a duplicate acknowledgement of this packet.

related segment

The selected packet is related to this packet in some other way, e.g. as part of reassembly.


The packet list has an Intelligent Scrollbar which shows a miniature map of nearby packets. Each raster line of the scrollbar corresponds to a single packet, so the number of packets shown in the map depends on your physical display and the height of the packet list. A tall packet list on a high-resolution (“Retina”) display will show you quite a few packets. In the image above the scrollbar shows the status of more than 500 packets along with the 15 shown in the packet list itself.

Right clicking will show a context menu, described in Figure 6.4, “Pop-up menu of the “Packet List” pane”.

3.18. The “Packet Details” Pane

The packet details pane shows the current packet (selected in the “Packet List” pane) in a more detailed form.

Figure 3.16. The “Packet Details” pane

ws details pane

This pane shows the protocols and protocol fields of the packet selected in the “Packet List” pane. The protocols and fields of the packet shown in a tree which can be expanded and collapsed.

There is a context menu (right mouse click) available. See details in Figure 6.5, “Pop-up menu of the “Packet Details” pane”.

Some protocol fields have special meanings.

  • Generated fields. Wireshark itself will generate additional protocol information which isn’t present in the captured data. This information is enclosed in square brackets (“[” and “]”). Generated information includes response times, TCP analysis, IP geolocation information, and checksum validation.
  • Links. If Wireshark detects a relationship to another packet in the capture file it will generate a link to that packet. Links are underlined and displayed in blue. If you double-clicked on a link Wireshark will jump to the corresponding packet.

3.19. The “Packet Bytes” Pane

The packet bytes pane shows the data of the current packet (selected in the “Packet List” pane) in a hexdump style.

Figure 3.17. The “Packet Bytes” pane

ws bytes pane

The “Packet Bytes” pane shows a canonical hex dump of the packet data. Each line contains the data offset, sixteen hexadecimal bytes, and sixteen ASCII bytes. Non-printalbe bytes are replaced with a period (“.”).

Depending on the packet data, sometimes more than one page is available, e.g. when Wireshark has reassembled some packets into a single chunk of data. (See Section 7.8, “Packet Reassembly” for details). In this case you can see each data source by clicking its corresponding tab at the bottom of the pane.

Figure 3.18. The “Packet Bytes” pane with tabs

ws bytes pane tabs

Additional pages typically contain data reassembled from multiple packets or decrypted data.

The context menu (right mouse click) of the tab labels will show a list of all available pages. This can be helpful if the size in the pane is too small for all the tab labels.

3.20. The Statusbar

The statusbar displays informational messages.

In general, the left side will show context related information, the middle part will show information about the current capture file, and the right side will show the selected configuration profile. Drag the handles between the text areas to change the size.

Figure 3.19. The initial Statusbar

ws statusbar empty

This statusbar is shown while no capture file is loaded, e.g. when Wireshark is started.

Figure 3.20. The Statusbar with a loaded capture file

ws statusbar loaded

  • The colorized bullet on the left shows the highest expert info level found in the currently loaded capture file. Hovering the mouse over this icon will show a textual description of the expert info level, and clicking the icon will bring up the Expert Infos dialog box. For a detailed description of expert info, see Section 7.4, “Expert Information”.
  • The left side shows information about the capture file, its name, its size and the elapsed time while it was being captured. Hovering over a file name will show its full path and size.
  • The middle part shows the current number of packets in the capture file. The following values are displayed:

    • Packets: The number of captured packets.
    • Displayed: The number of packets currently being displayed.
    • Marked: The number of marked packets (only displayed if packets are marked).
    • Dropped: The number of dropped packets (only displayed if Wireshark was unable to capture all packets).
    • Ignored: The number of ignored packets (only displayed if packets are ignored).
    • Load time: The time it took to load the capture (wall clock time).
  • The right side shows the selected configuration profile. Clicking in this part of the statusbar will bring up a menu with all available configuration profiles, and selecting from this list will change the configuration profile.

Figure 3.21. The Statusbar with a configuration profile menu

ws statusbar profile

For a detailed description of configuration profiles, see Section 11.6, “Configuration Profiles”.

Figure 3.22. The Statusbar with a selected protocol field

ws statusbar selected

This is displayed if you have selected a protocol field from the “Packet Details” pane.

[Tip] Tip

The value between the parentheses (in this example “ipv6.src”) can be used as a display filter, representing the selected protocol field.

Figure 3.23. The Statusbar with a display filter message

ws statusbar filter

This is displayed if you are trying to use a display filter which may have unexpected results. For a detailed description, see Section 6.4.7, “A Common Mistake”.

Chapter 4. Capturing Live Network Data

4.1. Introduction

Capturing live network data is one of the major features of Wireshark.

The Wireshark capture engine provides the following features:

  • Capture from different kinds of network hardware such as Ethernet or 802.11.
  • Stop the capture on different triggers such as the amount of captured data, elapsed time, or the number of packets.
  • Simultaneously show decoded packets while Wireshark is capturing.
  • Filter packets, reducing the amount of data to be captured. See Section 4.13, “Filtering while capturing”.
  • Save packets in multiple files while doing a long term capture, optionally rotating through a fixed number of files (a “ringbuffer”). See Section 4.11, “Capture files and file modes”.
  • Simultaneously capture from multiple network interfaces.

The capture engine still lacks the following features:

  • Stop capturing (or perform some other action) depending on the captured data.

4.2. Prerequisites

Setting up Wireshark to capture packets for the first time can be tricky. A comprehensive guide “How To setup a Capture” is available at https://wiki.wireshark.org/CaptureSetup.

Here are some common pitfalls:

  • You may need special privileges to start a live capture.
  • You need to choose the right network interface to capture packet data from.
  • You need to capture at the right place in the network to see the traffic you want to see.

If you have any problems setting up your capture environment you should have a look at the guide mentioned above.

4.3. Start Capturing

The following methods can be used to start capturing packets with Wireshark:

$ wireshark -i eth0 -k

This will start Wireshark capturing on interface eth0. More details can be found at Section 11.2, “Start Wireshark from the command line”.

4.4. The “Capture Interfaces” dialog box

When you select CaptureOptions…​ from the main menu Wireshark pops up the “Capture Interfaces” dialog box as shown in Figure 4.1, “The “Capture Interfaces” dialog box on Microsoft Windows” or Figure 4.2, “The “Capture Interfaces” dialog box on Unix/Linux”.

[Note] Both you and your OS can hide interfaces

This dialog box will only show the local interfaces Wireshark can access. It will also hide interfaces marked as hidden in Section 11.5.1, “Interface Options”. As Wireshark might not be able to detect all local interfaces and it cannot detect the remote interfaces available there could be more capture interfaces available than listed.

It is possible to select more than one interface and capture from them simultaneously.

Figure 4.1. The “Capture Interfaces” dialog box on Microsoft Windows

ws capture interfaces win32

Figure 4.2. The “Capture Interfaces” dialog box on Unix/Linux

ws capture interfaces

Device (Unix/Linux only)
The interface device name.
Description
The interface description provided by the operating system, or the user defined comment added in Section 11.5.1, “Interface Options”.
IP
The first IP address Wireshark could find for this interface. You can click on the address to cycle through other addresses assigned to it, if available. If no address could be found “none” will be displayed.
Packets
The number of packets captured from this interface, since this dialog was opened. Will be greyed out, if no packet was captured in the last second.
Packets/s
Number of packets captured in the last second. Will be greyed out, if no packet was captured in the last second.
Stop
Stop a currently running capture.
Start
Start a capture on all selected interfaces immediately, using the settings from the last capture or the default settings, if no options have been set.
Options
Open the Capture Options dialog with the marked interfaces selected. See Section 4.5, “The “Capture Options” dialog box”.
Details (Microsoft Windows only)
Open a dialog with detailed information about the interface. See Section 4.10, “The “Interface Details” dialog box”.
Help
Show this help page.
Close
Close this dialog box.

4.5. The “Capture Options” dialog box

When you select CaptureOptions…​ (or use the corresponding item in the main toolbar), Wireshark pops up the “Capture Options” dialog box as shown in Figure 4.3, “The “Capture Options” dialog box”.

Figure 4.3. The “Capture Options” dialog box

ws capture options

[Tip] Tip

If you are unsure which options to choose in this dialog box just try keeping the defaults as this should work well in many cases.

4.5.1. Capture frame

The table shows the settings for all available interfaces:

  • The name of the interface and its IP addresses. If no address could be resolved from the system, “none” will be shown.
[Note] Note

Loopback interfaces are not available on Windows platforms.

  • The link-layer header type.
  • The information whether promicuous mode is enabled or disabled.
  • The maximum amount of data that will be captured for each packet. The default value is set to the 262144 bytes.
  • The size of the kernel buffer that is reserved to keep the captured packets.
  • The information whether packets will be captured in monitor mode (Unix/Linux only).
  • The chosen capture filter.

By marking the checkboxes in the first column the interfaces are selected to be captured from. By double-clicking on an interface the “Edit Interface Settings” dialog box as shown in Figure 4.4, “The “Edit Interface Settings” dialog box” will be opened.

Capture on all interfaces
As Wireshark can capture on multiple interfaces it is possible to choose to capture on all available interfaces.
Capture all packets in promiscuous mode
This checkbox allows you to specify that Wireshark should put all interfaces in promiscuous mode when capturing.
Capture Filter

This field allows you to specify a capture filter for all interfaces that are currently selected. Once a filter has been entered in this field, the newly selected interfaces will inherit the filter. Capture filters are discussed in more details in Section 4.13, “Filtering while capturing”. It defaults to empty, or no filter.

You can also click on the Capture Filter button and Wireshark will bring up the Capture Filters dialog box and allow you to create and/or select a filter. Please see Section 6.6, “Defining and saving filters”

Compile selected BPFs
This button allows you to compile the capture filter into BPF code and pop up a window showing you the resulting pseudo code. This can help in understanding the working of the capture filter you created. The Compile Selected BPFs button leads you to Figure 4.5, “The “Compile Results” dialog box”.
[Tip] Tip

Linux power user tip

The execution of BPFs can be sped up on Linux by turning on BPF JIT by executing

$ echo 1 >/proc/sys/net/core/bpf_jit_enable

if it is not enabled already. To make the change persistent you can use sysfsutils.

Manage Interfaces
The Manage Interfaces button opens the Figure 4.6, “The “Add New Interfaces” dialog box” where pipes can be defined, local interfaces scanned or hidden, or remote interfaces added (Windows only).

4.5.2. Capture File(s) frame

An explanation about capture file usage can be found in Section 4.11, “Capture files and file modes”.

File

This field allows you to specify the file name that will be used for the capture file. This field is left blank by default. If the field is left blank, the capture data will be stored in a temporary file. See Section 4.11, “Capture files and file modes” for details.

You can also click on the button to the right of this field to browse through the filesystem.

Use multiple files
Instead of using a single file Wireshark will automatically switch to a new one if a specific trigger condition is reached.
Use pcapng format
This checkbox allows you to specify that Wireshark saves the captured packets in pcapng format. This next generation capture file format is currently in development. If more than one interface is chosen for capturing, this checkbox is set by default. See https://wiki.wireshark.org/Development/PcapNg for more details on pcapng.
Next file every n megabyte(s)
Multiple files only. Switch to the next file after the given number of byte(s)/kilobyte(s)/megabyte(s)/gigabyte(s) have been captured.
Next file every n minute(s)
Multiple files only: Switch to the next file after the given number of second(s)/minutes(s)/hours(s)/days(s) have elapsed.
Ring buffer with n files
Multiple files only: Form a ring buffer of the capture files with the given number of files.
Stop capture after n file(s)
Multiple files only: Stop capturing after switching to the next file the given number of times.

4.5.3. Stop Capture…​ frame

…​ after n packet(s)
Stop capturing after the given number of packets have been captured.
…​ after n megabytes(s)
Stop capturing after the given number of byte(s)/kilobyte(s)/megabyte(s)/gigabyte(s) have been captured. This option is greyed out if “Use multiple files” is selected.
…​ after n minute(s)
Stop capturing after the given number of second(s)/minutes(s)/hours(s)/days(s) have elapsed.

4.5.4. Display Options frame

Update list of packets in real time
This option allows you to specify that Wireshark should update the packet list pane in real time. If you do not specify this, Wireshark does not display any packets until you stop the capture. When you check this, Wireshark captures in a separate process and feeds the captures to the display process.
Automatic scrolling in live capture
This option allows you to specify that Wireshark should scroll the packet list pane as new packets come in, so you are always looking at the last packet. If you do not specify this Wireshark simply adds new packets onto the end of the list but does not scroll the packet list pane. This option is greyed out if “Update list of packets in real time” is disabled.

4.5.5. Name Resolution frame

Enable MAC name resolution
This option allows you to control whether or not Wireshark translates MAC addresses into names. See Section 7.9, “Name Resolution”.
Enable network name resolution
This option allows you to control whether or not Wireshark translates network addresses into names. See Section 7.9, “Name Resolution”.
Enable transport name resolution
This option allows you to control whether or not Wireshark translates transport addresses into protocols. See Section 7.9, “Name Resolution”.

4.5.6. Buttons

Once you have set the values you desire and have selected the options you need, simply click on Start to commence the capture or Cancel to cancel the capture.

4.6. The “Edit Interface Settings” dialog box

If you double-click on an interface in Figure 4.3, “The “Capture Options” dialog box” the following dialog box pops up.

Figure 4.4. The “Edit Interface Settings” dialog box

ws capture options settings

You can set the following fields in this dialog box:

IP address
The IP address(es) of the selected interface. If no address could be resolved from the system “none” will be shown.
Link-layer header type
Unless you are in the rare situation that requires this keep the default setting. For a detailed description. See Section 4.12, “Link-layer header type”
Wireless settings (Windows only)
Here you can set the settings for wireless capture using the AirPCap adapter. For a detailed description see the AirPCap Users Guide.
Remote settings (Windows only)
Here you can set the settings for remote capture. For a detailed description see Section 4.9, “The “Remote Capture Interfaces” dialog box”
Capture packets in promiscuous mode
This checkbox allows you to specify that Wireshark should put the interface in promiscuous mode when capturing. If you do not specify this Wireshark will only capture the packets going to or from your computer (not all packets on your LAN segment).
[Note] Note

If some other process has put the interface in promiscuous mode you may be capturing in promiscuous mode even if you turn off this option.

Even in promiscuous mode you still won’t necessarily see all packets on your LAN segment. See the Wireshark FAQ for more information.

Limit each packet to n bytes

This field allows you to specify the maximum amount of data that will be captured for each packet, and is sometimes referred to as the snaplen. If disabled the value is set to the maximum 65535 which will be sufficient for most protocols. Some rules of thumb:

  • If you are unsure just keep the default value.
  • If you don’t need or don’t want all of the data in a packet - for example, if you only need the link-layer, IP, and TCP headers - you might want to choose a small snapshot length, as less CPU time is required for copying packets, less buffer space is required for packets, and thus perhaps fewer packets will be dropped if traffic is very heavy.
  • If you don’t capture all of the data in a packet you might find that the packet data you want is in the part that’s dropped or that reassembly isn’t possible as the data required for reassembly is missing.
Buffer size: n megabyte(s)
Enter the buffer size to be used while capturing. This is the size of the kernel buffer which will keep the captured packets, until they are written to disk. If you encounter packet drops, try increasing this value.
Capture packets in monitor mode (Unix/Linux only)
This checkbox allows you to setup the Wireless interface to capture all traffic it can receive, not just the traffic on the BSS to which it is associated, which can happen even when you set promiscuous mode. Also it might be necessary to turn this option on in order to see IEEE 802.11 headers and/or radio information from the captured frames.
[Note] Note

In monitor mode the adapter might disassociate itself from the network it was associated to.

Capture Filter

This field allows you to specify a capture filter. Capture filters are discussed in more details in Section 4.13, “Filtering while capturing”. It defaults to empty, or no filter.

You can also click on the Capture Filter button and Wireshark will bring up the “Capture Filters” dialog box and allow you to create and/or select a filter. Please see Section 6.6, “Defining and saving filters”

Compile BPF
This button allows you to compile the capture filter into BPF code and pop up a window showing you the resulting pseudo code. This can help in understanding the working of the capture filter you created.

4.7. The “Compile Results” dialog box

This figure shows the compile results of the selected interfaces.

Figure 4.5. The “Compile Results” dialog box

ws capture options compile selected bpfs

In the left window the interface names are listed. The results of an individual interface are shown in the right window when it is selected.

4.8. The “Add New Interfaces” dialog box

As a central point to manage interfaces this dialog box consists of three tabs to add or remove interfaces.

Figure 4.6. The “Add New Interfaces” dialog box

ws capture options manage interfaces

4.8.1. Add or remove pipes

Figure 4.7. The “Add New Interfaces - Pipes” dialog box

ws capture options manage interfaces pipes

To successfully add a pipe, this pipe must have already been created. Click the New button and type the name of the pipe including its path. Alternatively, the Browse button can be used to locate the pipe. With the Save button the pipe is added to the list of available interfaces. Afterwards, other pipes can be added.

To remove a pipe from the list of interfaces it first has to be selected. Then click the Delete button.

4.8.2. Add or hide local interfaces

Figure 4.8. The “Add New Interfaces - Local Interfaces” dialog box

ws capture options manage interfaces local

The tab “Local Interfaces” contains a list of available local interfaces, including the hidden ones, which are not shown in the other lists.

If a new local interface is added, for example, a wireless interface has been activated, it is not automatically added to the list to prevent the constant scanning for a change in the list of available interfaces. To renew the list a rescan can be done.

One way to hide an interface is to change the preferences. If the “Hide” checkbox is activated and the Apply button clicked, the interface will not be seen in the lists of the “Capture Interfaces” dialog box any more. The changes are also saved in the preferences file.

4.8.3. Add or hide remote interfaces

Figure 4.9. The “Add New Interfaces - Remote Interfaces” dialog box

ws capture options manage interfaces remote

In this tab interfaces on remote hosts can be added. One or more of these interfaces can be hidden. In contrast to the local interfaces they are not saved in the preferences file.

To remove a host including all its interfaces from the list, it has to be selected. Then click the Delete button.

For a detailed description see Section 4.9, “The “Remote Capture Interfaces” dialog box”

4.9. The “Remote Capture Interfaces” dialog box

Besides doing capture on local interfaces Wireshark is capable of reaching out across the network to a so called capture daemon or service processes to receive captured data from.

[Note] Microsoft Windows only

This dialog and capability is only available on Microsoft Windows. On Linux/Unix you can achieve the same effect (securely) through an SSH tunnel.

The Remote Packet Capture Protocol service must first be running on the target platform before Wireshark can connect to it. The easiest way is to install WinPcap from https://www.winpcap.org/install/ on the target. Once installation is completed go to the Services control panel, find the Remote Packet Capture Protocol service and start it.

[Note] Note

Make sure you have outside access to port 2002 on the target platform. This is the port where the Remote Packet Capture Protocol service can be reached by default.

To access the Remote Capture Interfaces dialog use the “Add New Interfaces - Remote” dialog. See Figure 4.9, “The “Add New Interfaces - Remote Interfaces” dialog box” and select Add.

4.9.1. Remote Capture Interfaces

Figure 4.10. The “Remote Capture Interfaces” dialog box

ws capture options manage interfaces remote plus

You have to set the following parameters in this dialog:

Host
Enter the IP address or host name of the target platform where the Remote Packet Capture Protocol service is listening. The drop down list contains the hosts that have previously been successfully contacted. The list can be emptied by choosing “Clear list” from the drop down list.
Port
Set the port number where the Remote Packet Capture Protocol service is listening on. Leave open to use the default port (2002).
Null authentication
Select this if you don’t need authentication to take place for a remote capture to be started. This depends on the target platform. Configuring the target platform like this makes it insecure.
Password authentication
This is the normal way of connecting to a target platform. Set the credentials needed to connect to the Remote Packet Capture Protocol service.

4.9.2. Remote Capture Settings

The remote capture can be further fine tuned to match your situation. The Remote Settings button in Figure 4.4, “The “Edit Interface Settings” dialog box” gives you this option. It pops up the dialog shown in Figure 4.11, “The “Remote Capture Settings” dialog box”.

Figure 4.11. The “Remote Capture Settings” dialog box

ws capture options remote settings

You can set the following parameters in this dialog:

Do not capture own RPCAP traffic

This option sets a capture filter so that the traffic flowing back from the Remote Packet Capture Protocol service to Wireshark isn’t captured as well and also send back. The recursion in this saturates the link with duplicate traffic.

You only should switch this off when capturing on an interface other than the interface connecting back to Wireshark.

Use UDP for data transfer
Remote capture control and data flows over a TCP connection. This option allows you to choose an UDP stream for data transfer.
Sampling option None
This option instructs the Remote Packet Capture Protocol service to send back all captured packets which have passed the capture filter. This is usually not a problem on a remote capture session with sufficient bandwidth.
Sampling option 1 of x packets
This option limits the Remote Packet Capture Protocol service to send only a sub sampling of the captured data, in terms of number of packets. This allows capture over a narrow band remote capture session of a higher bandwidth interface.
Sampling option 1 every x milliseconds
This option limits the Remote Packet Capture Protocol service to send only a sub sampling of the captured data in terms of time. This allows capture over a narrow band capture session of a higher bandwidth interface.

4.10. The “Interface Details” dialog box

When you select Details from the Capture Interface menu, Wireshark pops up the “Interface Details” dialog box as shown in Figure 4.12, “The “Interface Details” dialog box”. This dialog shows various characteristics and statistics for the selected interface.

[Note] Microsoft Windows only

This dialog is only available on Microsoft Windows

Figure 4.12. The “Interface Details” dialog box

ws capture interface details

4.11. Capture files and file modes

While capturing the underlying libpcap capturing engine will grab the packets from the network card and keep the packet data in a (relatively) small kernel buffer. This data is read by Wireshark and saved into a capture file.

By default Wireshark saves packets to a temporary file. You can also tell Wireshark to save to a specific (“permanent”) file and switch to a different file after a given time has elapsed or a given number of packets have been captured. These options are controlled in the “Output” tab in the “Capture Options” dialog.

Figure 4.13. Capture output options

ws capture options output

[Tip] Tip

Working with large files (several hundred MB) can be quite slow. If you plan to do a long term capture or capturing from a high traffic network, think about using one of the “Multiple files” options. This will spread the captured packets over several smaller files which can be much more pleasant to work with.

Using Multiple files may cut context related information. Wireshark keeps context information of the loaded packet data, so it can report context related problems (like a stream error) and keeps information about context related protocols (e.g. where data is exchanged at the establishing phase and only referred to in later packets). As it keeps this information only for the loaded file, using one of the multiple file modes may cut these contexts. If the establishing phase is saved in one file and the things you would like to see is in another, you might not see some of the valuable context related information.

Information about the folders used for capture files can be found in Appendix B, Files and Folders.

Table 4.1. Capture file mode selected by capture options

File Name “Create a new file…​” “Use a ring buffer…​” Mode Resulting filename(s) used

-

-

-

Single temporary file

wiresharkXXXXXX (where XXXXXX is a unique number)

foo.cap

-

-

Single named file

foo.cap

foo.cap

x

-

Multiple files, continuous

foo_00001_20100205110102.cap, foo_00002_20100205110318.cap, …​

foo.cap

x

x

Multiple files, ring buffer

foo_00001_20100205110102.cap, foo_00002_20100205110318.cap, …​


Single temporary file
A temporary file will be created and used (this is the default). After capturing is stopped this file can be saved later under a user specified name.
Single named file
A single capture file will be used. If you want to place the new capture file in a specific folder choose this mode.
Multiple files, continuous
Like the “Single named file” mode, but a new file is created and used after reaching one of the multiple file switch conditions (one of the “Next file every …​” values).
Multiple files, ring buffer
Much like “Multiple files continuous”, reaching one of the multiple files switch conditions (one of the “Next file every …​” values) will switch to the next file. This will be a newly created file if value of “Ring buffer with n files” is not reached, otherwise it will replace the oldest of the formerly used files (thus forming a “ring”). + This mode will limit the maximum disk usage, even for an unlimited amount of capture input data, only keeping the latest captured data.

4.12. Link-layer header type

In most cases you won’t have to modify link-layer header type. Some exceaptions are as follows:

If you are capturing on an Ethernet device you might be offered a choice of “Ethernet” or “DOCSIS”. If you are capturing traffic from a Cisco Cable Modem Termination System that is putting DOCSIS traffic onto the Ethernet to be captured, select “DOCSIS”, otherwise select “Ethernet”.

If you are capturing on an 802.11 device on some versions of BSD you might be offered a choice of “Ethernet” or “802.11”. “Ethernet” will cause the captured packets to have fake (“cooked”) Ethernet headers. “802.11” will cause them to have full IEEE 802.11 headers. Unless the capture needs to be read by an application that doesn’t support 802.11 headers you should select “802.11”.

If you are capturing on an Endace DAG card connected to a synchronous serial line you might be offered a choice of “PPP over serial” or “Cisco HDLC”. If the protocol on the serial line is PPP, select “PPP over serial” and if the protocol on the serial line is Cisco HDLC, select “Cisco HDLC”.

If you are capturing on an Endace DAG card connected to an ATM network you might be offered a choice of “RFC 1483 IP-over-ATM” or “Sun raw ATM”. If the only traffic being captured is RFC 1483 LLC-encapsulated IP, or if the capture needs to be read by an application that doesn’t support SunATM headers, select “RFC 1483 IP-over-ATM”, otherwise select “Sun raw ATM”.

4.13. Filtering while capturing

Wireshark uses the libpcap filter language for capture filters. A brief overview of the syntax follows. Complete documentation can be found in the pcap-filter man page. You can find a lot of Capture Filter examples at https://wiki.wireshark.org/CaptureFilters.

You enter the capture filter into the “Filter” field of the Wireshark “Capture Options” dialog box, as shown in Figure 4.3, “The “Capture Options” dialog box”.

A capture filter takes the form of a series of primitive expressions connected by conjunctions (and/or) and optionally preceded by not:

[not] primitive [and|or [not] primitive ...]

An example is shown in Example 4.1, “A capture filter for telnet that captures traffic to and from a particular host”.

Example 4.1. A capture filter for telnet that captures traffic to and from a particular host

A capture filter for telnet that captures traffic to and from a particular host

tcp port 23 and host 10.0.0.5

This example captures telnet traffic to and from the host 10.0.0.5, and shows how to use two primitives and the and conjunction. Another example is shown in Example 4.2, “Capturing all telnet traffic not from 10.0.0.5”, and shows how to capture all telnet traffic except that from 10.0.0.5.

Example 4.2. Capturing all telnet traffic not from 10.0.0.5

Capturing all telnet traffic not from 10.0.0.5

tcp port 23 and not src host 10.0.0.5

A primitive is simply one of the following: [src|dst] host <host>
This primitive allows you to filter on a host IP address or name. You can optionally precede the primitive with the keyword src|dst to specify that you are only interested in source or destination addresses. If these are not present, packets where the specified address appears as either the source or the destination address will be selected.
ether [src|dst] host <ehost>
This primitive allows you to filter on Ethernet host addresses. You can optionally include the keyword src|dst between the keywords ether and host to specify that you are only interested in source or destination addresses. If these are not present, packets where the specified address appears in either the source or destination address will be selected.
gateway host <host>
This primitive allows you to filter on packets that used host as a gateway. That is, where the Ethernet source or destination was host but neither the source nor destination IP address was host.
[src|dst] net <net> [{mask <mask>}|{len <len>}]
This primitive allows you to filter on network numbers. You can optionally precede this primitive with the keyword src|dst to specify that you are only interested in a source or destination network. If neither of these are present, packets will be selected that have the specified network in either the source or destination address. In addition, you can specify either the netmask or the CIDR prefix for the network if they are different from your own.
[tcp|udp] [src|dst] port <port>

This primitive allows you to filter on TCP and UDP port numbers. You can optionally precede this primitive with the keywords src|dst and tcp|udp which allow you to specify that you are only interested in source or destination ports and TCP or UDP packets respectively. The keywords tcp|udp must appear before src|dst.

If these are not specified, packets will be selected for both the TCP and UDP protocols and when the specified address appears in either the source or destination port field.

less|greater <length>
This primitive allows you to filter on packets whose length was less than or equal to the specified length, or greater than or equal to the specified length, respectively.
ip|ether proto <protocol>
This primitive allows you to filter on the specified protocol at either the Ethernet layer or the IP layer.
ether|ip broadcast|multicast
This primitive allows you to filter on either Ethernet or IP broadcasts or multicasts.
<expr> relop <expr>
This primitive allows you to create complex filter expressions that select bytes or ranges of bytes in packets. Please see the pcap-filter man page at http://www.tcpdump.org/manpages/pcap-filter.7.html for more details.

4.13.1. Automatic Remote Traffic Filtering

If Wireshark is running remotely (using e.g. SSH, an exported X11 window, a terminal server, …​), the remote content has to be transported over the network, adding a lot of (usually unimportant) packets to the actually interesting traffic.

To avoid this, Wireshark tries to figure out if it’s remotely connected (by looking at some specific environment variables) and automatically creates a capture filter that matches aspects of the connection.

The following environment variables are analyzed:

SSH_CONNECTION (ssh)
<remote IP> <remote port> <local IP> <local port>
SSH_CLIENT (ssh)
<remote IP> <remote port> <local port>
REMOTEHOST (tcsh, others?)
<remote name>
DISPLAY (x11)
[remote name]:<display num>
SESSIONNAME (terminal server)
<remote name>

On Windows it asks the operating system if it’s running in a Remote Desktop Services environment.

4.14. While a Capture is running …​

You might see the following dialog box while a capture is running:

Figure 4.14. The “Capture Information” dialog box

ws capture info

This dialog box shows a list of protocols and their activity over time. It can be enabled via the “capture.show_info” setting in the “Advanced” preferences.

4.14.1. Stop the running capture

A running capture session will be stopped in one of the following ways:

  1. The Stop Capture button in the “Capture Information” dialog box.
  2. The CaptureStop menu item.
  3. The Stop toolbar button.
  4. Pressing Ctrl+E.
  5. The capture will be automatically stopped if one of the Stop Conditions is met, e.g. the maximum amount of data was captured.

4.14.2. Restart a running capture

A running capture session can be restarted with the same capture options as the last time, this will remove all packets previously captured. This can be useful, if some uninteresting packets are captured and there’s no need to keep them.

Restart is a convenience function and equivalent to a capture stop following by an immediate capture start. A restart can be triggered in one of the following ways:

  1. Using the CaptureRestart menu item.
  2. Using the Restart toolbar button.

Chapter 5. File Input, Output, and Printing

5.1. Introduction

This chapter will describe input and output of capture data.

  • Open capture files in various capture file formats
  • Save/Export capture files in various capture file formats
  • Merge capture files together
  • Import text files containing hex dumps of packets
  • Print packets

5.2. Open capture files

Wireshark can read in previously saved capture files. To read them, simply select the FileOpen menu or toolbar item. Wireshark will then pop up the “File Open” dialog box, which is discussed in more detail in Section 5.2.1, “The “Open Capture File” dialog box”.

[Tip] It’s convenient to use drag-and-drop

You can open a file by simply dragging it in your file manager and dropping it onto Wireshark’s main window. However, drag-and-drop may not be available in all desktop environments.

If you haven’t previously saved the current capture file you will be asked to do so to prevent data loss. This warning can be disabled in the preferences.

In addition to its native file format (pcapng), Wireshark can read and write capture files from a large number of other packet capture programs as well. See Section 5.2.2, “Input File Formats” for the list of capture formats Wireshark understands.

5.2.1. The “Open Capture File” dialog box

The “Open Capture File” dialog box allows you to search for a capture file containing previously captured packets for display in Wireshark. The following sections show some examples of the Wireshark “Open File” dialog box. The appearance of this dialog depends on the system. However, the functionality should be the same across systems.

Common dialog behaviour on all systems:

  • Select files and directories.
  • Click the Open or OK button to accept your selected file and open it.
  • Click the Cancel button to go back to Wireshark and not load a capture file.

Wireshark extensions to the standard behaviour of these dialogs:

  • View file preview information such as the filesize and the number of packets in a selected a capture file.
  • Specify a display filter with the Filter button and filter field. This filter will be used when opening the new file. The text field background becomes green for a valid filter string and red for an invalid one. Clicking on the Filter button causes Wireshark to pop up the “Filters” dialog box (which is discussed further in Section 6.3, “Filtering packets while viewing”).
  • Specify which type of name resolution is to be performed for all packets by clicking on one of the “…​ name resolution” check buttons. Details about name resolution can be found in Section 7.9, “Name Resolution”.
[Tip] Save a lot of time loading huge capture files

You can change the display filter and name resolution settings later while viewing the packets. However, loading huge capture files can take a significant amount of extra time if these settings are changed later, so in such situations it can be a good idea to set at least the filter in advance here.

Figure 5.1. “Open” on Microsoft Windows

ws open win32

This is the common Windows file open dialog - plus some Wireshark extensions.

Specific for this dialog:

  • The Help button will lead you to this section of this “User’s Guide”.

Figure 5.2. “Open” - Linux and UNIX

ws open gtk24

This is the common Gimp/GNOME file open dialog plus some Wireshark extensions.

Specific for this dialog:

  • The + button allows you to add a directory selected in the right-hand pane to the favorites list on the left. These changes are persistent.
  • The - button allows you to remove a selected directory from the list. Some items (such as “Desktop”) cannot be removed from the favorites list.
  • If Wireshark doesn’t recognize the selected file as a capture file it will grey out the Open button.

5.2.2. Input File Formats

The following file formats from other capture tools can be opened by Wireshark:

  • pcapng. A flexible, etensible successor to the libpcap format. Wireshark 1.8 and later save files as pcapng by default. Versions prior to 1.8 used libpcap.
  • libpcap. The default format used by the libpcap packet capture library. Used by tcpdump, _Snort, Nmap, Ntop, and many other tools.
  • Oracle (previously Sun) snoop and atmsnoop
  • Finisar (previously Shomiti) Surveyor captures
  • Microsoft Network Monitor captures
  • Novell LANalyzer captures
  • AIX iptrace captures
  • Cinco Networks NetXray captures
  • Network Associates Windows-based Sniffer and Sniffer Pro captures
  • Network General/Network Associates DOS-based Sniffer (compressed or uncompressed) captures
  • AG Group/WildPackets/Savvius EtherPeek/TokenPeek/AiroPeek/EtherHelp/PacketGrabber captures
  • RADCOM’s WAN/LAN Analyzer captures
  • Network Instruments Observer version 9 captures
  • Lucent/Ascend router debug output
  • HP-UX’s nettl
  • Toshiba’s ISDN routers dump output
  • ISDN4BSD i4btrace utility
  • traces from the EyeSDN USB S0
  • IPLog format from the Cisco Secure Intrusion Detection System
  • pppd logs (pppdump format)
  • the output from VMS’s TCPIPtrace/TCPtrace/UCX$TRACE utilities
  • the text output from the DBS Etherwatch VMS utility
  • Visual Networks’ Visual UpTime traffic capture
  • the output from CoSine L2 debug
  • the output from Accellent’s 5Views LAN agents
  • Endace Measurement Systems’ ERF format captures
  • Linux Bluez Bluetooth stack hcidump -w traces
  • Catapult DCT2000 .out files
  • Gammu generated text output from Nokia DCT3 phones in Netmonitor mode
  • IBM Series (OS/400) Comm traces (ASCII & UNICODE)
  • Juniper Netscreen snoop captures
  • Symbian OS btsnoop captures
  • Tamosoft CommView captures
  • Textronix K12xx 32bit .rf5 format captures
  • Textronix K12 text file format captures
  • Apple PacketLogger captures
  • Captures from Aethra Telecommunications’ PC108 software for their test instruments

New file formats are added from time to time.

It may not be possible to read some formats dependent on the packet types captured. Ethernet captures are usually supported for most file formats but it may not be possible to read other packet types such as PPP or IEEE 802.11 from all file formats.

5.3. Saving captured packets

You can save captured packets simply by using the FileSave As…​ menu item. You can choose which packets to save and which file format to be used.

Not all information will be saved in a capture file. For example, most file formats don’t record the number of dropped packets. See Section B.1, “Capture Files” for details.

5.3.1. The “Save Capture File As” dialog box

The “Save Capture File As” dialog box allows you to save the current capture to a file. The following sections show some examples of this dialog box. The appearance of this dialog depends on the system. However, the functionality should be the same across systems.

Figure 5.3. “Save” on Microsoft Windows

ws save as win32

This is the common Windows file save dialog with some additional Wireshark extensions.

Specific behavior for this dialog:

  • If available, the “Help” button will lead you to this section of this “User’s Guide”.
  • If you don’t provide a file extension to the filename (e.g. .pcap) Wireshark will append the standard file extension for that file format.

Figure 5.4. “Save” on Linux and UNIX

ws save as gtk24

This is the common Gimp/GNOME file save dialog with additional Wireshark extensions.

Specific for this dialog:

  • Clicking on the + at “Browse for other folders” will allow you to browse files and folders in your file system.

With this dialog box, you can perform the following actions:

  1. Type in the name of the file you wish to save the captured packets in, as a standard file name in your file system.
  2. Select the directory to save the file into.
  3. Select the range of the packets to be saved. See Section 5.9, “The “Packet Range” frame”.
  4. Specify the format of the saved capture file by clicking on the File type drop down box. You can choose from the types described in Section 5.3.2, “Output File Formats”.

Some capture formats may not be available depending on the packet types captured.

[Tip] Wireshark can convert file formats

You can convert capture files from one format to another by reading in a capture file and writing it out using a different format.

  1. Click the Save or OK button to accept your selected file and save to it. If Wireshark has a problem saving the captured packets to the file you specified it will display an error dialog box. After clicking OK on that error dialog box you can try again.
  2. Click on the Cancel button to go back to Wireshark without saving any packets.

5.3.2. Output File Formats

Wireshark can save the packet data in its native file format (pcapng) and in the file formats of other protocol analyzers so other tools can read the capture data.

[Warning] Different file formats have different time stamp accuracies

Saving from the currently used file format to a different format may reduce the time stamp accuracy; see the Section 7.6, “Time Stamps” for details.

The following file formats can be saved by Wireshark (with the known file extensions):

  • pcapng (*.pcapng). A flexible, etensible successor to the libpcap format. Wireshark 1.8 and later save files as pcapng by default. Versions prior to 1.8 used libpcap.
  • libpcap, tcpdump and various other tools using tcpdump’s capture format (*.pcap,*.cap,*.dmp)
  • Accellent 5Views (*.5vw)
  • HP-UX’s nettl (*.TRC0,*.TRC1)
  • Microsoft Network Monitor - NetMon (*.cap)
  • Network Associates Sniffer - DOS (*.cap,*.enc,*.trc,*fdc,*.syc)
  • Network Associates Sniffer - Windows (*.cap)
  • Network Instruments Observer version 9 (*.bfr)
  • Novell LANalyzer (*.tr1)
  • Oracle (previously Sun) snoop (*.snoop,*.cap)
  • Visual Networks Visual UpTime traffic (*.*)

New file formats are added from time to time.

Whether or not the above tools will be more helpful than Wireshark is a different question ;-)

[Note] Third party protocol analyzers may require specific file extensions

Wireshark examines a file’s contents to determine its type. Some other protocol analyzers only look at a filename extensions. For example, you might need to use the .cap extension in order to open a file using Sniffer.

5.4. Merging capture files

Sometimes you need to merge several capture files into one. For example, this can be useful if you have captured simultaneously from multiple interfaces at once (e.g. using multiple instances of Wireshark).

There are three ways to merge capture files using Wireshark:

  • Use the FileMerge menu to open the “Merge” dialog. See Section 5.4.1, “The “Merge with Capture File” dialog box”. This menu item will be disabled unless you have loaded a capture file.
  • Use drag-and-drop to drop multiple files on the main window. Wireshark will try to merge the packets in chronological order from the dropped files into a newly created temporary file. If you drop only a single file it will simply replace the existing capture.
  • Use the mergecap tool, a command line tool to merge capture files. This tool provides the most options to merge capture files. See Section D.8, “mergecap: Merging multiple capture files into one” for details.

5.4.1. The “Merge with Capture File” dialog box

This dialog box let you select a file to be merged into the currently loaded file. If your current data has not been saved you will be asked to save it first.

Most controls of this dialog will work the same way as described in the “Open Capture File” dialog box, see Section 5.2.1, “The “Open Capture File” dialog box”.

Specific controls of this merge dialog are:

Prepend packets to existing file
Prepend the packets from the selected file before the currently loaded packets.
Merge packets chronologically
Merge both the packets from the selected and currently loaded file in chronological order.
Append packets to existing file
Append the packets from the selected file after the currently loaded packets.

Figure 5.5. “Merge” on Microsoft Windows

ws merge win32

This is the common Windows file open dialog with additional Wireshark extensions.

Figure 5.6. “Merge” on Linux and UNIX

ws merge gtk24

This is the common Gimp/GNOME file open dialog with additional Wireshark extensions.

5.5. Import hex dump

Wireshark can read in an ASCII hex dump and write the data described into a temporary libpcap capture file. It can read hex dumps with multiple packets in them, and build a capture file of multiple packets. It is also capable of generating dummy Ethernet, IP and UDP, TCP, or SCTP headers, in order to build fully processable packet dumps from hexdumps of application-level data only.

Wireshark understands a hexdump of the form generated by od -Ax -tx1 -v. In other words, each byte is individually displayed and surrounded with a space. Each line begins with an offset describing the position in the file. The offset is a hex number (can also be octal or decimal), of more than two hex digits. Here is a sample dump that can be imported:

000000 00 e0 1e a7 05 6f 00 10 ........
000008 5a a0 b9 12 08 00 46 00 ........
000010 03 68 00 00 00 00 0a 2e ........
000018 ee 33 0f 19 08 7f 0f 19 ........
000020 03 80 94 04 00 00 10 01 ........
000028 16 a2 0a 00 03 50 00 0c ........
000030 01 01 0f 19 03 80 11 01 ........

There is no limit on the width or number of bytes per line. Also the text dump at the end of the line is ignored. Byte and hex numbers can be uppercase or lowercase. Any text before the offset is ignored, including email forwarding characters >. Any lines of text between the bytestring lines are ignored. The offsets are used to track the bytes, so offsets must be correct. Any line which has only bytes without a leading offset is ignored. An offset is recognized as being a hex number longer than two characters. Any text after the bytes is ignored (e.g. the character dump). Any hex numbers in this text are also ignored. An offset of zero is indicative of starting a new packet, so a single text file with a series of hexdumps can be converted into a packet capture with multiple packets. Packets may be preceded by a timestamp. These are interpreted according to the format given. If not the first packet is timestamped with the current time the import takes place. Multiple packets are read in with timestamps differing by one microsecond each. In general, short of these restrictions, Wireshark is pretty liberal about reading in hexdumps and has been tested with a variety of mangled outputs (including being forwarded through email multiple times, with limited line wrap etc.)

There are a couple of other special features to note. Any line where the first non-whitespace character is # will be ignored as a comment. Any line beginning with #TEXT2PCAP is a directive and options can be inserted after this command to be processed by Wireshark. Currently there are no directives implemented. In the future these may be used to give more fine grained control on the dump and the way it should be processed e.g. timestamps, encapsulation type etc. Wireshark also allows the user to read in dumps of application-level data, by inserting dummy L2, L3 and L4 headers before each packet. The user can elect to insert Ethernet headers, Ethernet and IP, or Ethernet, IP and UDP/TCP/SCTP headers before each packet. This allows Wireshark or any other full-packet decoder to handle these dumps.

5.5.1. The “Import from Hex Dump” dialog box

This dialog box lets you select a text file, containing a hex dump of packet data, to be imported and set import parameters.

Figure 5.7. The “Import from Hex Dump” dialog

ws file import

Specific controls of this import dialog are split in two sections:

Input
Determine which input file has to be imported and how it is to be interpreted.
Import
Determine how the data is to be imported.

The input parameters are as follows:

Filename / Browse
Enter the name of the text file to import. You can use Browse to browse for a file.
Offsets
Select the radix of the offsets given in the text file to import. This is usually hexadecimal, but decimal and octal are also supported.
Date/Time
Tick this checkbox if there are timestamps associated with the frames in the text file to import you would like to use. Otherwise the current time is used for timestamping the frames.
Format
This is the format specifier used to parse the timestamps in the text file to import. It uses a simple syntax to describe the format of the timestamps, using %H for hours, %M for minutes, %S for seconds, etc. The straightforward HH:MM:SS format is covered by %T. For a full definition of the syntax look for strptime(3).

The import parameters are as follows:

Encapsulation type
Here you can select which type of frames you are importing. This all depends on from what type of medium the dump to import was taken. It lists all types that Wireshark understands, so as to pass the capture file contents to the right dissector.
Dummy header
When Ethernet encapsulation is selected you have to option to prepend dummy headers to the frames to import. These headers can provide artificial Ethernet, IP, UDP or TCP or SCTP headers, SCTP data chunks or ExportPDU. When selecting a type of dummy header the applicable entries are enabled, others are grayed out and default values are used.
Maximum frame length
You may not be interested in the full frames from the text file, just the first part. Here you can define how much data from the start of the frame you want to import. If you leave this open the maximum is set to 65535 bytes.

Once all input and import parameters are setup click OK to start the import. If your current data wasn’t saved before you will be asked to save it first.

When completed there will be a new capture file loaded with the frames imported from the text file.

5.6. File Sets

When using the “Multiple Files” option while doing a capture (see: Section 4.11, “Capture files and file modes”), the capture data is spread over several capture files, called a file set.

As it can become tedious to work with a file set by hand, Wireshark provides some features to handle these file sets in a convenient way.

The following features in the FileFile Set submenu are available to work with file sets in a convenient way:

  • The “List Files” dialog box will list the files Wireshark has recognized as being part of the current file set.
  • Next File closes the current and opens the next file in the file set.
  • Previous File closes the current and opens the previous file in the file set.

5.6.1. The “List Files” dialog box

Figure 5.8. The “List Files” dialog box

ws file set dialog

Each line contains information about a file of the file set:

  • Filename the name of the file. If you click on the filename (or the radio button left to it), the current file will be closed and the corresponding capture file will be opened.
  • Created the creation time of the file
  • Last Modified the last time the file was modified
  • Size the size of the file

The last line will contain info about the currently used directory where all of the files in the file set can be found.

The content of this dialog box is updated each time a capture file is opened/closed.

The Close button will, well, close the dialog box.

5.7. Exporting data

Wireshark provides several ways and formats to export packet data. This section describes general ways to export data from the main Wireshark application. There are more specialized functions to export specific data which are described elsewhere.

5.7.1. The “Export as Plain Text File” dialog box

Export packet data into a plain ASCII text file, much like the format used to print packets.

[Tip] Tip

If you would like to be able to import any previously exported packets from a plain text file it is recommended that you:

  • Add the “Absolute date and time” column.
  • Temporarily hide all other columns.
  • Disable the EditPreferencesProtocolsData “Show not dissected data on new Packet Bytes pane” preference. More details are provided in Section 11.5, “Preferences”
  • Include the packet summary line.
  • Exclude column headings.
  • Exclude packet details.
  • Include the packet bytes.

Figure 5.9. The “Export as Plain Text File” dialog box

ws export plain

5.7.2. The “Export as PostScript File” dialog box

Figure 5.10. The “Export as PostScript File” dialog box

ws export ps

5.7.3. The “Export as CSV (Comma Separated Values) File” dialog box

Export packet summary into CSV, used e.g. by spreadsheet programs to im-/export data.

5.7.4. The “Export as C Arrays (packet bytes) file” dialog box

Export packet bytes into C arrays so you can import the stream data into your own C program.

5.7.5. The “Export as PSML File” dialog box

Export packet data into PSML. This is an XML based format including only the packet summary. The PSML file specification is available at: http://www.nbee.org/doku.php?id=netpdl:psml_specification.

Figure 5.11. The “Export as PSML File” dialog box

ws export psml

There’s no such thing as a packet details frame for PSML export, as the packet format is defined by the PSML specification.

5.7.6. The “Export as PDML File” dialog box

Export packet data into PDML. This is an XML based format including the packet details. The PDML file specification is available at: http://www.nbee.org/doku.php?id=netpdl:pdml_specification.

[Note] Note

The PDML specification is not officially released and Wireshark’s implementation of it is still in an early beta state, so please expect changes in future Wireshark versions.

Figure 5.12. The “Export as PDML File” dialog box

ws export pdml

There’s no such thing as a packet details frame for PDML export, as the packet format is defined by the PDML specification.

5.7.7. The “Export selected packet bytes” dialog box

Export the bytes selected in the “Packet Bytes” pane into a raw binary file.

Figure 5.13. The “Export Selected Packet Bytes” dialog box

ws export selected

  • Name: the filename to export the packet data to.
  • The Save in folder: field lets you select the folder to save to (from some predefined folders).
  • Browse for other folders provides a flexible way to choose a folder.

5.7.8. The “Export Objects” dialog box

This feature scans through the selected protocol’s streams in the currently open capture file or running capture and allows the user to export reassembled objects to the disk. For example, if you select HTTP, you can export HTML documents, images, executables, and any other files transferred over HTTP to the disk. If you have a capture running, this list is automatically updated every few seconds with any new objects seen. The saved objects can then be opened or examined independently of Wireshark.

Figure 5.14. The “Export Objects” dialog box

ws export objects

Columns:

  • Packet: The packet number in which this object was found. In some cases, there can be multiple objects in the same packet.
  • Hostname: The hostname of the server that sent this object.
  • Content Type: The content type of this object.
  • Size: The size of this object in bytes.
  • Filename: The filename for this object. Each protocol generates the filename differently. For example, HTTP uses the final part of the URI and IMF uses the subject of the email.

Inputs:

  • Text Filter: Only displays objects containing the specified text string.
  • Help: Opens the “Export Objects” section in the user’s guide.
  • Save All: Saves all objects (including those not displayed) using the filename from the filename column. You will be asked what directory / folder to save them in.
  • Close: Closes the “Export Objects” dialog.
  • Save: Saves the currently selected object as a filename you specify. The default filename to save as is taken from the filename column of the objects list.

5.8. Printing packets

To print packets, select the FilePrint…​ menu item. When you do this Wireshark pops up the “Print” dialog box as shown in Figure 5.15, “The “Print” dialog box”.

5.8.1. The “Print” dialog box

Figure 5.15. The “Print” dialog box

ws print

The following fields are available in the Print dialog box: Printer

This field contains a pair of mutually exclusive radio buttons:

  • Plain Text specifies that the packet print should be in plain text.
  • PostScript specifies that the packet print process should use PostScript to generate a better print output on PostScript aware printers.
  • Output to file: specifies that printing be done to a file, using the filename entered in the field or selected with the browse button.

    This field is where you enter the file to print to if you have selected Print to a file, or you can click the button to browse the filesystem. It is greyed out if Print to a file is not selected.

  • Print command specifies that a command be used for printing.

    [Note] Note!

    These Print command fields are not available on windows platforms.

    This field specifies the command to use for printing. It is typically lpr. You would change it to specify a particular queue if you need to print to a queue other than the default. An example might be:

    $ lpr -Pmypostscript

    This field is greyed out if Output to file: is checked above.

Packet Range
Select the packets to be printed, see Section 5.9, “The “Packet Range” frame”
Packet Format
Select the output format of the packets to be printed. You can choose, how each packet is printed, see Figure 5.17, “The “Packet Format” frame”

5.9. The “Packet Range” frame

The packet range frame is a part of various output related dialog boxes. It provides options to select which packets should be processed by the output function.

Figure 5.16. The “Packet Range” frame

ws packet range

If the Captured button is set (default), all packets from the selected rule will be processed. If the Displayed button is set, only the currently displayed packets are taken into account to the selected rule.

  • All packets will process all packets.
  • Selected packet only process only the selected packet.
  • Marked packets only process only the marked packets.
  • From first to last marked packet process the packets from the first to the last marked one.
  • Specify a packet range process a user specified range of packets, e.g. specifying 5,10-15,20- will process the packet number five, the packets from packet number ten to fifteen (inclusive) and every packet from number twenty to the end of the capture.

5.10. The Packet Format frame

The packet format frame is a part of various output related dialog boxes. It provides options to select which parts of a packet should be used for the output function.

Figure 5.17. The “Packet Format” frame

ws packet format

  • Packet summary line enable the output of the summary line, just as in the “Packet List” pane.
  • Packet details enable the output of the packet details tree.
  • All collapsed the info from the “Packet Details” pane in “all collapsed” state.
  • As displayed the info from the “Packet Details” pane in the current state.
  • All expanded the info from the “Packet Details” pane in “all expanded” state.
  • Packet bytes enable the output of the packet bytes, just as in the “Packet Bytes” pane.
  • Each packet on a new page put each packet on a separate page (e.g. when saving/printing to a text file, this will put a form feed character between the packets).

Chapter 6. Working with captured packets

6.1. Viewing packets you have captured

Once you have captured some packets or you have opened a previously saved capture file, you can view the packets that are displayed in the packet list pane by simply clicking on a packet in the packet list pane, which will bring up the selected packet in the tree view and byte view panes.

You can then expand any part of the tree to view detailed information about each protocol in each packet. Clicking on an item in the tree will highlight the corresponding bytes in the byte view. An example with a TCP packet selected is shown in Figure 6.1, “Wireshark with a TCP packet selected for viewing”. It also has the Acknowledgment number in the TCP header selected, which shows up in the byte view as the selected bytes.

Figure 6.1. Wireshark with a TCP packet selected for viewing

ws packet selected

You can also select and view packets the same way while Wireshark is capturing if you selected “Update list of packets in real time” in the “Capture Preferences” dialog box.

In addition you can view individual packets in a separate window as shown in Figure 6.2, “Viewing a packet in a separate window”. You can do this by double-clicking on an item in the packet list or by selecting the packet in which you are interested in the packet list pane and selecting ViewShow Packet in New Window. This allows you to easily compare two or more packets, even across multiple files.

Figure 6.2. Viewing a packet in a separate window

ws packet sep win

Along with double-clicking the packet list and using the main menu there are a number of other ways to open a new packet window:

6.2. Pop-up menus

You can bring up a pop-up menu over either the “Packet List”, its column header, or “Packet Details” pane by clicking your right mouse button at the corresponding pane.

6.2.1. Pop-up menu of the “Packet List” column header

Figure 6.3. Pop-up menu of the “Packet List” column header

ws column header popup menu

The following table gives an overview of which functions are available in this header, where to find the corresponding function in the main menu, and a short description of each item.

Table 6.1. The menu items of the “Packet List” column header pop-up menu

Item Identical to main menu’s item: Description

Sort Ascending

 

Sort the packet list in ascending order based on this column.

Sort Descending

 

Sort the packet list in descending order based on this column.

No Sort

 

Remove sorting order based on this column.

Align Left

 

Set left alignment of the values in this column.

Align Center

 

Set center alignment of the values in this column.

Align Right

 

Set right alignment of the values in this column.

Column Preferences…​

 

Open the Preferences dialog box on the column tab.

Resize Column

 

Resize the column to fit the values.

Rename Column Title

 

Allows you to change the title of the column header.

Displayed Column

View

This menu items folds out with a list of all configured columns. These columns can now be shown or hidden in the packet list.

Hide Column

 

Allows you to hide the column from the packet list.

Remove Column

 

Allows you to remove the column from the packet list.


6.2.2. Pop-up menu of the “Packet List” pane

Figure 6.4. Pop-up menu of the “Packet List” pane

ws packet pane popup menu

The following table gives an overview of which functions are available in this pane, where to find the corresponding function in the main menu, and a short description of each item.

Table 6.2. The menu items of the “Packet List” pop-up menu

Item Identical to main menu’s item: Description

Mark Packet (toggle)

Edit

Mark/unmark a packet.

Ignore Packet (toggle)

Edit

Ignore or inspect this packet while dissecting the capture file.

Set Time Reference (toggle)

Edit

Set/reset a time reference.

Manually Resolve Address

 

Allows you to enter a name to resolve for the selected address.

Apply as Filter

Analyze

Prepare and apply a display filter based on the currently selected item.

Prepare a Filter

Analyze

Prepare a display filter based on the currently selected item.

Conversation Filter

 

This menu item applies a display filter with the address information from the selected packet. E.g. the IP menu entry will set a filter to show the traffic between the two IP addresses of the current packet. XXX - add a new section describing this better.

Colorize Conversation

 

This menu item uses a display filter with the address information from the selected packet to build a new colorizing rule.

SCTP

 

Allows you to analyze and prepare a filter for this SCTP association.

Follow TCP Stream

Analyze

Allows you to view all the data on a TCP stream between a pair of nodes.

Follow UDP Stream

Analyze

Allows you to view all the data on a UDP datagram stream between a pair of nodes.

Follow TLS Stream

Analyze

Same as “Follow TCP Stream” but for TLS or SSL. XXX - add a new section describing this better.

Copy/ Summary (Text)

 

Copy the summary fields as displayed to the clipboard, as tab-separated text.

Copy/ Summary (CSV)

 

Copy the summary fields as displayed to the clipboard, as comma-separated text.

Copy/ As Filter

 

Prepare a display filter based on the currently selected item and copy that filter to the clipboard.

Copy/ Bytes (Offset Hex Text)

 

Copy the packet bytes to the clipboard in hexdump-like format.

Copy/ Bytes (Offset Hex)

 

Copy the packet bytes to the clipboard in hexdump-like format, but without the text portion.

Copy/ Bytes (Printable Text Only)

 

Copy the packet bytes to the clipboard as ASCII text, excluding non-printable characters.

Copy/ Bytes (Hex Stream)

 

Copy the packet bytes to the clipboard as an unpunctuated list of hex digits.

Copy/ Bytes (Binary Stream)

 

Copy the packet bytes to the clipboard as raw binary. The data is stored in the clipboard as MIME-type “application/octet-stream”.

Decode As…​

Analyze

Change or apply a new relation between two dissectors.

Print…​

File

Print packets.

Show Packet in New Window

View

Display the selected packet in a new window.


6.2.3. Pop-up menu of the “Packet Details” pane

Figure 6.5. Pop-up menu of the “Packet Details” pane

ws details pane popup menu

The following table gives an overview of which functions are available in this pane, where to find the corresponding function in the main menu, and a short description of each item.

Table 6.3. The menu items of the “Packet Details” pop-up menu

Item Identical to main menu’s item: Description

Expand Subtrees

View

Expand the currently selected subtree.

Collapse Subtrees

View

Collapse the currently selected subtree.

Expand All

View

Expand all subtrees in all packets in the capture.

Collapse All

View

Wireshark keeps a list of all the protocol subtrees that are expanded, and uses it to ensure that the correct subtrees are expanded when you display a packet. This menu item collapses the tree view of all packets in the capture list.

Apply as Column

 

Use the selected protocol item to create a new column in the packet list.

Apply as Filter

Analyze

Prepare and apply a display filter based on the currently selected item.

Prepare a Filter

Analyze

Prepare a display filter based on the currently selected item.

Colorize with Filter

 

This menu item uses a display filter with the information from the selected protocol item to build a new colorizing rule.

Follow TCP Stream

Analyze

Allows you to view all the data on a TCP stream between a pair of nodes.

Follow UDP Stream

Analyze

Allows you to view all the data on a UDP datagram stream between a pair of nodes.

Follow TLS Stream

Analyze

Same as “Follow TCP Stream” but for TLS. XXX - add a new section describing this better.

Copy/ Description

Edit

Copy the displayed text of the selected field to the system clipboard.

Copy/ Fieldname

Edit

Copy the name of the selected field to the system clipboard.

Copy/ Value

Edit

Copy the value of the selected field to the system clipboard.

Copy/ As Filter

Edit

Prepare a display filter based on the currently selected item and copy it to the clipboard.

Copy/ Bytes (Offset Hex Text)

 

Copy the packet bytes to the clipboard in hexdump-like format; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Offset Hex)

 

Copy the packet bytes to the clipboard in hexdump-like format, but without the text portion; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Printable Text Only)

 

Copy the packet bytes to the clipboard as ASCII text, excluding non-printable characters; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Hex Stream)

 

Copy the packet bytes to the clipboard as an unpunctuated list of hex digits; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Binary Stream)

 

Copy the packet bytes to the clipboard as raw binary; similar to the Packet List Pane command, but copies only the bytes relevant to the selected part of the tree (the bytes selected in the Packet Bytes Pane). The data is stored in the clipboard as MIME-type “application/octet-stream”.

Export Selected Packet Bytes…​

File

This menu item is the same as the File menu item of the same name. It allows you to export raw packet bytes to a binary file.

Wiki Protocol Page

 

Show the wiki page corresponding to the currently selected protocol in your web browser.

Filter Field Reference

 

Show the filter field reference web page corresponding to the currently selected protocol in your web browser.

Protocol Preferences…​

 

The menu item takes you to the properties dialog and selects the page corresponding to the protocol if there are properties associated with the highlighted field. More information on preferences can be found in Figure 11.7, “The preferences dialog box”.

Decode As…​

Analyze

Change or apply a new relation between two dissectors.

Disable Protocol

 

Allows you to temporarily disable a protocol dissector, which may be blocking the legitimate dissector.

Resolve Name

View

Causes a name resolution to be performed for the selected packet, but NOT every packet in the capture.

Go to Corresponding Packet

Go

If the selected field has a corresponding packet, go to it. Corresponding packets will usually be a request/response packet pair or such.


6.3. Filtering packets while viewing

Wireshark has two filtering languages: One used when capturing packets, and one used when displaying packets. In this section we explore that second type of filter: Display filters. The first one has already been dealt with in Section 4.13, “Filtering while capturing”.

Display filters allow you to concentrate on the packets you are interested in while hiding the currently uninteresting ones. They allow you to select packets by:

  • Protocol
  • The presence of a field
  • The values of fields
  • A comparison between fields
  • …​ and a lot more!

To select packets based on protocol type, simply type the protocol in which you are interested in the Filter: field in the filter toolbar of the Wireshark window and press enter to initiate the filter. Figure 6.6, “Filtering on the TCP protocol” shows an example of what happens when you type tcp in the filter field.

[Note] Note

All protocol and field names are entered in lowercase. Also, don’t forget to press enter after entering the filter expression.

Figure 6.6. Filtering on the TCP protocol

ws display filter tcp

As you might have noticed, only packets of the TCP protocol are displayed now (e.g. packets 1-10 are hidden). The packet numbering will remain as before, so the first packet shown is now packet number 11.

[Note] Note

When using a display filter, all packets remain in the capture file. The display filter only changes the display of the capture file but not its content!

You can filter on any protocol that Wireshark understands. You can also filter on any field that a dissector adds to the tree view, but only if the dissector has added an abbreviation for the field. A list of such fields is available in Wireshark in the Add Expression…​ dialog box. You can find more information on the Add Expression…​ dialog box in Section 6.5, “The “Filter Expression” dialog box”.

For example, to narrow the packet list pane down to only those packets to or from the IP address 192.168.0.1, use ip.addr==192.168.0.1.

[Note] Note

To remove the filter, click on the Clear button to the right of the filter field.

6.4. Building display filter expressions

Wireshark provides a simple but powerful display filter language that allows you to build quite complex filter expressions. You can compare values in packets as well as combine expressions into more specific expressions. The following sections provide more information on doing this.

[Tip] Tip

You will find a lot of Display Filter examples at the Wireshark Wiki Display Filter page at: https://wiki.wireshark.org/DisplayFilters.

6.4.1. Display filter fields

Every field in the packet details pane can be used as a filter string, this will result in showing only the packets where this field exists. For example: the filter string: tcp will show all packets containing the tcp protocol.

There is a complete list of all filter fields available through the menu item HelpSupported Protocols in the page “Display Filter Fields” of the “Supported Protocols” dialog.

6.4.2. Comparing values

You can build display filters that compare values using a number of different comparison operators. They are shown in Table 6.4, “Display Filter comparison operators”.

[Tip] Tip

You can use English and C-like terms in the same way, they can even be mixed in a filter string.

Table 6.4. Display Filter comparison operators

English C-like Description and example

eq

==

Equal. ip.src==10.0.0.5

ne

!=

Not equal. ip.src!=10.0.0.5

gt

>

Greater than. frame.len > 10

lt

<

Less than. frame.len < 128

ge

>=

Greater than or equal to. frame.len ge 0x100

le

<=

Less than or equal to. frame.len <= 0x20

contains

 

Protocol, field or slice contains a value. sip.To contains "a1762"

matches

~

Protocol or text field match Perl regualar expression. http.host matches "acme\.(org|com|net)"

bitwise_and

&

Compare bit field value. tcp.flags & 0x02


In addition, all protocol fields have a type. Display Filter Field Types provides a list of the types and example of how to express them.

Display Filter Field Types

Unsigned integer

Can be 8, 16, 24, 32, or 64 bits. You can express integers in decimal, octal, or hexadecimal. The following display filters are equivalent:

ip.len le 1500
ip.len le 02734
ip.len le 0x5dc
Signed integer
Can be 8, 16, 24, 32, or 64 bits. As with unsigned integers you can use decimal, octal, or hexadecimal.
Boolean

A boolean field is present in the protocol decode only if its value is true. For example, tcp.flags.syn is present, and thus true, only if the SYN flag is present in a TCP segment header.

The filter expression  `tcp.flags.syn` will select only  those packets for which
this flag exists, that is,  TCP segments where the segment header contains the
SYN flag. Similarly, to find source-routed token ring packets, use a filter
expression of  `tr.sr`.
Ethernet address

6 bytes separated by a colon (:), dot (.) or dash (-) with one or two bytes between separators:

eth.dst == ff:ff:ff:ff:ff:ff
eth.dst == ff-ff-ff-ff-ff-ff
eth.dst == ffff.ffff.ffff
IPv4 address

ip.addr == 192.168.0.1

Classless InterDomain Routing (CIDR) notation can be used to test if
an IPv4 address is in a certain subnet. For example, this display
filter will find all packets in the 129.111 Class-B network:
ip.addr == 129.111.0.0/16
IPv6 address

ipv6.addr == ::1

As with IPv4 addresses, IPv6 addresses can match a subnet.
Text string
http.request.uri == "https://www.wireshark.org/"
udp contains 81:60:03

The example above match packets that contains the 3-byte sequence 0x81, 0x60, 0x03 anywhere in the UDP header or payload.

sip.To contains "a1762"

Above example match packets where SIP To-header contains the string "a1762" anywhere in the header.

http.host matches "acme\.(org|com|net)"

The example above match HTTP packets where the HOST header contains acme.org or acme.com or acme.net. Comparisons are case-insensitive. Note: Wireshark needs to be built with libpcre in order to be able to use the matches resp. {tilde} operator.

tcp.flags & 0x02

That expression will match all packets that contain a “tcp.flags” field with the 0x02 bit, i.e. the SYN bit, set.

6.4.3. Combining expressions

You can combine filter expressions in Wireshark using the logical operators shown in Table 6.5, “Display Filter Logical Operations”

Table 6.5. Display Filter Logical Operations

English C-like Description and example

and

&&

Logical AND. ip.src==10.0.0.5 and tcp.flags.fin

or

||

Logical OR. ip.scr==10.0.0.5 or ip.src==192.1.1.1

xor

^^

Logical XOR. tr.dst[0:3] == 0.6.29 xor tr.src[0:3] == 0.6.29

not

!

Logical NOT. not llc

[…​]

 

See “Slice Operator” below.

in

 

See “Membership Operator” below.


6.4.4. Slice Operator

Wireshark allows you to select subsequences of a sequence in rather elaborate ways. After a label you can place a pair of brackets [] containing a comma separated list of range specifiers.

eth.src[0:3] == 00:00:83

The example above uses the n:m format to specify a single range. In this case n is the beginning offset and m is the length of the range being specified.

eth.src[1-2] == 00:83

The example above uses the n-m format to specify a single range. In this case n is the beginning offset and m is the ending offset.

eth.src[:4] == 00:00:83:00

The example above uses the :m format, which takes everything from the beginning of a sequence to offset m. It is equivalent to 0:m

eth.src[4:] == 20:20

The example above uses the n: format, which takes everything from offset n to the end of the sequence.

eth.src[2] == 83

The example above uses the n format to specify a single range. In this case the element in the sequence at offset n is selected. This is equivalent to n:1.

eth.src[0:3,1-2,:4,4:,2] ==
00:00:83:00:83:00:00:83:00:20:20:83

Wireshark allows you to string together single ranges in a comma separated list to form compound ranges as shown above.

6.4.5. Membership Operator

Wireshark allows you to test a field for membership in a set of values or fields. After the field name, use the in operator followed by the set items surrounded by braces {}.

tcp.port in {80 443 8080}

This can be considered a shortcut operator, as the previous expression could have been expressed as:

tcp.port == 80 || tcp.port == 443 || tcp.port == 8080

The set of values can also contain ranges:

tcp.port in {443 4430..4434}

This is not merely a shortcut for tcp.port == 443 || (tcp.port >= 4430 && tcp.port <= 4434). Comparison operators are usually satisfied when any field matches the filter, and thus a packet with ports 80 and 56789 would match this alternative display filter since 56789 >= 4430 && 80 <= 4434 is true. The membership operator instead tests the same field against the range condition.

Sets are not just limited to numbers, other types can be used as well:

http.request.method in {"HEAD" "GET"}
ip.addr in {10.0.0.5 .. 10.0.0.9 192.168.1.1..192.168.1.9}
frame.time_delta in {10 .. 10.5}

6.4.6. Functions

The display filter language has a number of functions to convert fields, see Table 6.6, “Display Filter Functions”.

Table 6.6. Display Filter Functions

Function Description

upper

Converts a string field to uppercase.

lower

Converts a string field to lowercase.

len

Returns the byte length of a string or bytes field.

count

Returns the number of field occurrences in a frame.


The upper and lower functions can used to force case-insensitive matches: lower(http.server) contains "apache".

To find HTTP requests with long request URIs: len(http.request.uri) > 100. Note that the len function yields the string length in bytes rather than (multi-byte) characters.

Usually an IP frame has only two addresses (source and destination), but in case of ICMP errors or tunneling, a single packet might contain even more addresses. These packets can be found with count(ip.addr) > 2.

6.4.7. A Common Mistake

Using the != operator on combined expressions like eth.addr, ip.addr, tcp.port, and udp.port will probably not work as expected. Wireshark will show the warning “"!=" is deprecated or may have unexpected results” when you use it.

Often people use a filter string to display something like ip.addr == 1.2.3.4 which will display all packets containing the IP address 1.2.3.4.

Then they use ip.addr != 1.2.3.4 to see all packets not containing the IP address 1.2.3.4 in it. Unfortunately, this does not do the expected.

Instead, that expression will even be true for packets where either source or destination IP address equals 1.2.3.4. The reason for this, is that the expression ip.addr != 1.2.3.4 must be read as “the packet contains a field named ip.addr with a value different from 1.2.3.4”. As an IP datagram contains both a source and a destination address, the expression will evaluate to true whenever at least one of the two addresses differs from 1.2.3.4.

If you want to filter out all packets containing IP datagrams to or from IP address 1.2.3.4, then the correct filter is !(ip.addr == 1.2.3.4) as it reads “show me all the packets for which it is not true that a field named ip.addr exists with a value of 1.2.3.4”, or in other words, “filter out all packets for which there are no occurrences of a field named ip.addr with the value 1.2.3.4”.

6.4.8. Sometimes Fields Change Names

As protocols evolve they sometimes change names or are superseded by newer standards. For example, DHCP extends and has largely replaced BOOTP and TLS has replaced SSL. If a protocol dissector originally used the older names and fields for a protocol the Wireshark development team might update it to use the newer names and fields. In such cases they will add an alias from the old protocol name to the new one in order to make the transition easier.

For example, the DHCP dissector was originally developed for the BOOTP protocol but as of Wireshark 3.0 all of the “bootp” display filter fields have been renamed to their “dhcp” equivalents. You can still use the old filter names for the time being, e.g. “bootp.type” is equivalent to “dhcp.type” but Wireshark will show the warning “"bootp.type" is deprecated or may have unexpected results” when you use it. Support for the deprecated fields may be removed in the future.

6.5. The “Filter Expression” dialog box

When you are accustomed to Wireshark’s filtering system and know what labels you wish to use in your filters it can be very quick to simply type a filter string. However if you are new to Wireshark or are working with a slightly unfamiliar protocol it can be very confusing to try to figure out what to type. The “Filter Expression” dialog box helps with this.

[Tip] Tip

The “Filter Expression” dialog box is an excellent way to learn how to write Wireshark display filter strings.

Figure 6.7. The “Filter Expression” dialog box

ws filter add expression

When you first bring up the Filter Expression dialog box you are shown a tree of field names, organized by protocol, and a box for selecting a relation.

Field Name
Select a protocol field from the protocol field tree. Every protocol with filterable fields is listed at the top level. (You can search for a particular protocol entry by entering the first few letters of the protocol name). By expanding a protocol name you can get a list of the field names available for filtering for that protocol.
Relation
Select a relation from the list of available relation. The is present is a unary relation which is true if the selected field is present in a packet. All other listed relations are binary relations which require additional data (e.g. a Value to match) to complete.

When you select a field from the field name list and select a binary relation (such as the equality relation ==) you will be given the opportunity to enter a value, and possibly some range information.

Value
You may enter an appropriate value in the Value text box. The Value will also indicate the type of value for the field name you have selected (like character string).
Predefined values
Some of the protocol fields have predefined values available, much like enum’s in C. If the selected protocol field has such values defined, you can choose one of them here.
Range
A range of integers or a group of ranges, such as 1-12 or 39-42,98-2000.
OK
When you have built a satisfactory expression click OK and a filter string will be built for you.
Cancel
You can leave the “Add Expression…​” dialog box without any effect by clicking the Cancel button.

6.6. Defining and saving filters

You can define filters with Wireshark and give them labels for later use. This can save time in remembering and retyping some of the more complex filters you use.

To define a new filter or edit an existing one, select CaptureCapture Filters…​ or AnalyzeDisplay Filters…​. Wireshark will then pop up the Filters dialog as shown in Figure 6.8, “The “Capture Filters” and “Display Filters” dialog boxes”.

The mechanisms for defining and saving capture filters and display filters are almost identical. Both will be described here but the differences between these two will be marked as such.

[Warning] Warning

You must use Save to save your filters permanently. OK or Apply will not save the filters and they will be lost when you close Wireshark.

Figure 6.8. The “Capture Filters” and “Display Filters” dialog boxes

ws filters

New
This button adds a new filter to the list of filters. The currently entered values from Filter name and Filter string will be used. If any of these fields are empty, it will be set to “new”.
Delete
This button deletes the selected filter. It will be greyed out, if no filter is selected.
Filter
You can select a filter from this list (which will fill in the filter name and filter string in the fields down at the bottom of the dialog box).
Filter name:

You can change the name of the currently selected filter here.

The filter name will only be used in this dialog to identify the filter for your convenience, it will not be used elsewhere. You can add multiple filters with the same name, but this is not very useful.

Filter string:
You can change the filter string of the currently selected filter here. Display Filter only: the string will be syntax checked while you are typing.
Add Expression…​
Display Filter only: This button brings up the Add Expression dialog box which assists in building filter strings. You can find more information about the Add Expression dialog in Section 6.5, “The “Filter Expression” dialog box”
OK
Display Filter only: This button applies the selected filter to the current display and closes the dialog.
Apply
Display Filter only: This button applies the selected filter to the current display, and keeps the dialog open.
Save
Save the current settings in this dialog. The file location and format is explained in Appendix B, Files and Folders.
Close
Close this dialog. This will discard unsaved settings.

6.7. Defining and saving filter macros

You can define filter macros with Wireshark and give them labels for later use. This can save time in remembering and retyping some of the more complex filters you use.

6.8. Finding packets

You can easily find packets once you have captured some packets or have read in a previously saved capture file. Simply select the Find Packet…​ menu item from the Edit menu. Wireshark will pop up the dialog box shown in Figure 6.9, “The “Find Packet” dialog box”.

6.8.1. The “Find Packet” dialog box

Figure 6.9. The “Find Packet” dialog box

ws find packet

You might first select the kind of thing to search for:

  • Display filter

    Simply enter a display filter string into the Filter: field, select a direction, and click on OK.

    For example, to find the three way handshake for a connection from host 192.168.0.1, use the following filter string:

ip.src==192.168.0.1 and tcp.flags.syn==1

For more details on display filters, see Section 6.3, “Filtering packets while viewing”

  • Hex Value

    Search for a specific byte sequence in the packet data.

    For example, use “00:00” to find the next packet including two null bytes in the packet data.

  • String

    Find a string in the packet data, with various options.

    The value to be found will be syntax checked while you type it in. If the syntax check of your value succeeds, the background of the entry field will turn green, if it fails, it will turn red.

You can choose the search direction:

  • Up

    Search upwards in the packet list (decreasing packet numbers).

  • Down

    Search downwards in the packet list (increasing packet numbers).

6.8.2. The “Find Next” command

“Find Next” will continue searching with the same options used in the last “Find Packet”.

6.8.3. The “Find Previous” command

“Find Previous” will do the same thing as “Find Next”, but in the reverse direction.

6.9. Go to a specific packet

You can easily jump to specific packets with one of the menu items in the Go menu.

6.9.1. The “Go Back” command

Go back in the packet history, works much like the page history in current web browsers.

6.9.2. The “Go Forward” command

Go forward in the packet history, works much like the page history in current web browsers.

6.9.3. The “Go to Packet” dialog box

Figure 6.10. The “Go To Packet” dialog box

ws goto packet

This dialog box will let you enter a packet number. When you press OK, Wireshark will jump to that packet.

6.9.4. The “Go to Corresponding Packet” command

If a protocol field is selected which points to another packet in the capture file, this command will jump to that packet.

As these protocol fields now work like links (just as in your Web browser), it’s easier to simply double-click on the field to jump to the corresponding field.

6.9.5. The “Go to First Packet” command

This command will simply jump to the first packet displayed.

6.9.6. The “Go to Last Packet” command

This command will simply jump to the last packet displayed.

6.10. Marking packets

You can mark packets in the “Packet List” pane. A marked packet will be shown with black background, regardless of the coloring rules set. Marking a packet can be useful to find it later while analyzing in a large capture file.

The packet marks are not stored in the capture file or anywhere else. All packet marks will be lost when you close the capture file.

You can use packet marking to control the output of packets when saving, exporting, or printing. To do so, an option in the packet range is available, see Section 5.9, “The “Packet Range” frame”.

There are three functions to manipulate the marked state of a packet:

  • Mark packet (toggle) toggles the marked state of a single packet.
  • Mark all displayed packets set the mark state of all displayed packets.
  • Unmark all packets reset the mark state of all packets.

These mark functions are available from the “Edit” menu, and the “Mark packet (toggle)” function is also available from the pop-up menu of the “Packet List” pane.

6.11. Ignoring packets

You can ignore packets in the “Packet List” pane. Wireshark will then pretend that this packets does not exist in the capture file. An ignored packet will be shown with white background and gray foreground, regardless of the coloring rules set.

The packet ignored marks are not stored in the capture file or anywhere else. All “packet ignored” marks will be lost when you close the capture file.

There are three functions to manipulate the ignored state of a packet:

  • Ignore packet (toggle) toggles the ignored state of a single packet.
  • Ignore all displayed packets set the ignored state of all displayed packets.
  • Un-Ignore all packets reset the ignored state of all packets.

These ignore functions are available from the “Edit” menu, and the “Ignore packet (toggle)” function is also available from the pop-up menu of the “Packet List” pane.

6.12. Time display formats and time references

While packets are captured, each packet is timestamped. These timestamps will be saved to the capture file, so they will be available for later analysis.

A detailed description of timestamps, timezones and alike can be found at: Section 7.6, “Time Stamps”.

The timestamp presentation format and the precision in the packet list can be chosen using the View menu, see Figure 3.5, “The “View” Menu”.

The available presentation formats are:

  • Date and Time of Day: 1970-01-01 01:02:03.123456 The absolute date and time of the day when the packet was captured.
  • Time of Day: 01:02:03.123456 The absolute time of the day when the packet was captured.
  • Seconds Since Beginning of Capture: 123.123456 The time relative to the start of the capture file or the first “Time Reference” before this packet (see Section 6.12.1, “Packet time referencing”).
  • Seconds Since Previous Captured Packet: 1.123456 The time relative to the previous captured packet.
  • Seconds Since Previous Displayed Packet: 1.123456 The time relative to the previous displayed packet.
  • Seconds Since Epoch (1970-01-01): 1234567890.123456 The time relative to epoch (midnight UTC of January 1, 1970).

The available precisions (aka. the number of displayed decimal places) are:

  • Automatic The timestamp precision of the loaded capture file format will be used (the default).
  • Seconds, Deciseconds, Centiseconds, Milliseconds, Microseconds or Nanoseconds The timestamp precision will be forced to the given setting. If the actually available precision is smaller, zeros will be appended. If the precision is larger, the remaining decimal places will be cut off.

Precision example: If you have a timestamp and it’s displayed using, “Seconds Since Previous Packet” the value might be 1.123456. This will be displayed using the “Automatic” setting for libpcap files (which is microseconds). If you use Seconds it would show simply 1 and if you use Nanoseconds it shows 1.123456000.

6.12.1. Packet time referencing

The user can set time references to packets. A time reference is the starting point for all subsequent packet time calculations. It will be useful, if you want to see the time values relative to a special packet, e.g. the start of a new request. It’s possible to set multiple time references in the capture file.

The time references will not be saved permanently and will be lost when you close the capture file.

Time referencing will only be useful if the time display format is set to “Seconds Since Beginning of Capture”. If one of the other time display formats are used, time referencing will have no effect (and will make no sense either).

To work with time references, choose one of the Time Reference] items in the menu:[Edit menu or from the pop-up menu of the “Packet List” pane. See Section 3.6, “The “Edit” Menu”.

  • Set Time Reference (toggle) Toggles the time reference state of the currently selected packet to on or off.
  • Find Next Find the next time referenced packet in the “Packet List” pane.
  • Find Previous Find the previous time referenced packet in the “Packet List” pane.

Figure 6.11. Wireshark showing a time referenced packet

ws time reference

A time referenced packet will be marked with the string *REF* in the Time column (see packet number 10). All subsequent packets will show the time since the last time reference.

Chapter 7. Advanced Topics

7.1. Introduction

This chapter will describe some of Wireshark’s advanced features.

7.2. Following Protocol Streams

It can be very helpful to see protocol in the way that the application layer sees it. Perhaps you are looking for passwords in a Telnet stream, or you are trying to make sense of a data stream. Maybe you just need a display filter to show only the packets in a TLS or SSL stream. If so, Wireshark’s ability to follow protocol streams will be useful to you.

Simply select a TCP, UDP, TLS, or HTTP packet in the packet list of the stream/connection you are interested in and then select the Follow TCP Stream menu item from the Wireshark Tools menu (or use the context menu in the packet list). Wireshark will set an appropriate display filter and pop up a dialog box with all the data from the TCP stream laid out in order, as shown in Figure 7.1, “The “Follow TCP Stream” dialog box”.

[Tip] Tip

Following a protocol stream applies a display filter which selects all the packets in the current stream. Some people open the “Follow TCP Stream” dialog and immediately close it as a quick way to isolate a particular stream. Closing the dialog with the “Back” button will reset the display filter if this behavior is not desired.

Figure 7.1. The “Follow TCP Stream” dialog box

ws follow stream

The stream content is displayed in the same sequence as it appeared on the network. Traffic from A to B is marked in red, while traffic from B to A is marked in blue. If you like, you can change these colors in the “Font and Colors” page in the “Preferences” dialog.

Non-printable characters will be replaced by dots.

The stream content won’t be updated while doing a live capture. To get the latest content you’ll have to reopen the dialog.

You can choose from the following actions:

Help
Show this help.
Filter out this stream
Apply a display filter removing the current stream data from the display.
Print
Print the stream data in the currently selected format.
Save as…​
Save the stream data in the currently selected format.
Back
Close this dialog box and restore the previous display filter.
Close
Close this dialog box, leaving the current display filter in effect.

By default data from both directions is displayed. You can select the Entire conversation to switch between both, client to server, or server to client data.

You can choose to view the data in one of the following formats:

ASCII
In this view you see the data from each direction in ASCII. Obviously best for ASCII based protocols, e.g. HTTP.
C Arrays
This allows you to import the stream data into your own C program.
EBCDIC
For the big-iron freaks out there.
HEX Dump
This allows you to see all the data. This will require a lot of screen space and is best used with binary protocols.
UTF-8
Like ASCII, but decode the data as UTF-8.
UTF-16
Like ASCII, but decode the data as UTF-16.
YAML
This allows you to load the stream as YAML.
Raw
This allows you to load the unaltered stream data into a different program for further examination. The display will look the same as the ASCII setting, but “Save As” will result in a binary file.

You can switch between streams using the “Stream” selector.

You can search for text by entering it in the “Find” entry box and pressing Find Next.

7.3. Show Packet Bytes

If a selected packet field does not show all the bytes (i.e. they are truncated when displayed) or if they are shown as bytes rather than string or if they require more formatting because they contain an image or HTML then this dialog can be used.

This dialog can also be used to decode field bytes from base64, zlib compressed or quoted-printable and show the decoded bytes as configurable output. It’s also possible to select a subset of bytes setting the start byte and end byte.

You can choose from the following actions:

Help
Show this help.
Print
Print the bytes in the currently selected format.
Copy
Copy the bytes to the clipboard in the currently selected format.
Save As
Save the bytes in the currently selected format.
Close
Close this dialog box.

You can choose to decode the data from one of the following formats:

None
This is the default which does not decode anything.
Base64
This will decode from Base64.
Compressed
This will decompress the buffer using zlib.
Quoted-Printable
This will decode from a Quoted-Printable string.
ROT-13
This will decode ROT-13 encoded text.

You can choose to view the data in one of the following formats:

ASCII
In this view you see the bytes as ASCII. All control characters and non-ASCII bytes are replaced by dot.
ASCII & Control
In this view all control characters are shown using a UTF-8 symbol and all non-ASCII bytes are replaced by dot.
C Array
This allows you to import the field data into your own C program.
EBCDIC
For the big-iron freaks out there.
Hex Dump
This allows you to see all the data. This will require a lot of screen space and is best used with binary protocols.
HTML
This allows you to see all the data formatted as a HTML document. The HTML supported is what’s supported by the Qt QTextEdit class.
Image
This will try to convert the bytes into an image. Most popular formats are supported including PNG, JPEG, GIF, and BMP.
ISO 8859-1
In this view you see the bytes as ISO 8859-1.
Raw
This allows you to load the unaltered stream data into a different program for further examination. The display will show HEX data, but “Save As” will result in a binary file.
UTF-8
In this view you see the bytes as UTF-8.
UTF-16
In this view you see the bytes as UTF-16.
YAML
This will show the bytes as a YAML binary dump.

You can search for text by entering it in the “Find” entry box and pressing Find Next.

7.4. Expert Information

The expert infos is a kind of log of the anomalies found by Wireshark in a capture file.

The general idea behind the following “Expert Info” is to have a better display of “uncommon” or just notable network behaviour. This way, both novice and expert users will hopefully find probable network problems a lot faster, compared to scanning the packet list “manually” .

[Warning] Expert infos are only a hint

Take expert infos as a hint what’s worth looking at, but not more. For example, the absence of expert infos doesn’t necessarily mean everything is OK.

The amount of expert infos largely depends on the protocol being used. While some common protocols like TCP/IP will show detailed expert infos, most other protocols currently won’t show any expert infos at all.

The following will first describe the components of a single expert info, then the User Interface.

7.4.1. Expert Info Entries

Each expert info will contain the following things which will be described in detail below.

Table 7.1. Some example expert infos

Packet # Severity Group Protocol Summary

1

Note

Sequence

TCP

Duplicate ACK (#1)

2

Chat

Sequence

TCP

Connection reset (RST)

8

Note

Sequence

TCP

Keep-Alive

9

Warn

Sequence

TCP

Fast retransmission (suspected)


7.4.1.1. Severity

Every expert info has a specific severity level. The following severity levels are used, in parentheses are the colors in which the items will be marked in the GUI:

  • Chat (grey): information about usual workflow, e.g. a TCP packet with the SYN flag set
  • Note (cyan): notable things, e.g. an application returned an “usual” error code like HTTP 404
  • Warn (yellow): warning, e.g. application returned an “unusual” error code like a connection problem
  • Error (red): serious problem, e.g. [Malformed Packet]

7.4.1.2. Group

There are some common groups of expert infos. The following are currently implemented:

  • Checksum: a checksum was invalid
  • Sequence: protocol sequence suspicious, e.g. sequence wasn’t continuous or a retransmission was detected or …​
  • Response Code: problem with application response code, e.g. HTTP 404 page not found
  • Request Code: an application request (e.g. File Handle == x), usually Chat level
  • Undecoded: dissector incomplete or data can’t be decoded for other reasons
  • Reassemble: problems while reassembling, e.g. not all fragments were available or an exception happened while reassembling
  • Protocol: violation of protocol specs (e.g. invalid field values or illegal lengths), dissection of this packet is probably continued
  • Malformed: malformed packet or dissector has a bug, dissection of this packet aborted
  • Debug: debugging (should not occur in release versions)

It’s possible that more groups will be added in the future.

7.4.1.3. Protocol

The protocol in which the expert info was caused.

7.4.1.4. Summary

Each expert info will also have a short additional text with some further explanation.

7.4.2. “Expert Info” dialog

You can open the expert info dialog by selecting AnalyzeExpert Info.

Figure 7.2. The “Expert Info” dialog box

ws expert infos

7.4.2.1. Errors / Warnings / Notes / Chats tabs

An easy and quick way to find the most interesting infos (rather than using the Details tab), is to have a look at the separate tabs for each severity level. As the tab label also contains the number of existing entries, it’s easy to find the tab with the most important entries.

There are usually a lot of identical expert infos only differing in the packet number. These identical infos will be combined into a single line - with a count column showing how often they appeared in the capture file. Clicking on the plus sign shows the individual packet numbers in a tree view.

7.4.2.2. Details tab

The Details tab provides the expert infos in a “log like” view, each entry on its own line (much like the packet list). As the amount of expert infos for a capture file can easily become very large, getting an idea of the interesting infos with this view can take quite a while. The advantage of this tab is to have all entries in the sequence as they appeared, this is sometimes a help to pinpoint problems.

7.4.3. “Colorized” Protocol Details Tree

Figure 7.3. The “Colorized” protocol details tree

ws expert colored tree

The protocol field causing an expert info is colorized, e.g. uses a cyan background for a note severity level. This color is propagated to the toplevel protocol item in the tree, so it’s easy to find the field that caused the expert info.

For the example screenshot above, the IP “Time to live” value is very low (only 1), so the corresponding protocol field is marked with a cyan background. To easier find that item in the packet tree, the IP protocol toplevel item is marked cyan as well.

7.4.4. “Expert” Packet List Column (optional)

Figure 7.4. The “Expert” packet list column

ws expert column

An optional “Expert Info Severity” packet list column is available that displays the most significant severity of a packet or stays empty if everything seems OK. This column is not displayed by default but can be easily added using the Preferences Columns page described in Section 11.5, “Preferences”.

7.5. TCP Analysis

By default, Wireshark’s TCP dissector tracks the state of each TCP session and provides additional information when problems or potential problems are detected. Analysis is done once for each TCP packet when a capture file is first opened. Packets are processed in the order in which they appear in the packet list. You can enable or disable this feature via the “Analyze TCP sequence numbers” TCP dissector preference.

For analysis of data or protocols layered on top of TCP (such as HTTP), see Section 7.8.3, “TCP Reassembly”.

Figure 7.5. “TCP Analysis” packet detail items

ws tcp analysis

TCP Analysis flags are added to the TCP protocol tree under “SEQ/ACK analysis”. Each flag is described below. Terms such as “next expected sequence number” and “next expected acknowledgement number” refer to the following”:

Next expected sequence number
The last-seen sequence number plus segment length. Set when there are no analysis flags and and for zero window probes. This is initially zero and calculated based on the previous packet in the same TCP flow. Note that this may not be the same as the tcp.nxtseq protocol field.
Next expected acknowledgement number
The last-seen sequence number for segments. Set when there are no analysis flags and for zero window probes.
Last-seen acknowledgment number
Always set. Note that this is not the same as the next expected acknowledgment number.
Last-seen acknowledgment number
Always updated for each packet. Note that this is not the same as the next expected acknowledgment number.

TCP ACKed unseen segment

Set when the expected next acknowledgement number is set for the reverse direction and it’s less than the current acknowledgement number.

TCP Dup ACK <frame>#<acknowledgement number>

Set when all of the following are true:

  • The segment size is zero.
  • The window size is non-zero and hasn’t changed.
  • The next expected sequence number and last-seen acknowledgment number are non-zero (i.e. the connection has been established).
  • SYN, FIN, and RST are not set.

TCP Fast Retransmission

Set when all of the following are true:

  • This is not a keepalive packet.
  • In the forward direction, the segment size is greater than zero or the SYN or FIN is set.
  • The next expected sequence number is greater than the current sequence number.
  • We have more than two duplicate ACKs in the reverse direction.
  • The current sequence number equals the next expected acknowledgement number.
  • We saw the last acknowledgement less than 20ms ago.

Supersedes “Out-Of-Order”, “Spurious Retransmission”, and “Retransmission”.

TCP Keep-Alive

Set when the segment size is zero or one, the current sequence number is one byte less than the next expected sequence number, and any of SYN, FIN, or RST are set.

Supersedes “Fast Retransmission”, “Out-Of-Order”, “Spurious Retransmission”, and “Retransmission”.

TCP Keep-Alive ACK

Set when all of the following are true:

  • The segment size is zero.
  • The window size is non-zero and hasn’t changed.
  • The current sequence number is the same as the next expected sequence number.
  • The current acknowledgement number is the same as the last-seen acknowledgement number.
  • The most recently seen packet in the reverse direction was a keepalive.
  • The packet is not a SYN, FIN, or RST.

Supersedes “Dup ACK” and “ZeroWindowProbeAck”.

TCP Out-Of-Order

Set when all of the following are true:

  • This is not a keepalive packet.
  • In the forward direction, the segment length is greater than zero or the SYN or FIN is set.
  • The next expected sequence number is greater than the current sequence number.
  • The next expected sequence number and the next sequence number differ.
  • The last segment arrived within the calculated RTT (3ms by default).

Supersedes “Spurious Retransmission” and “Retransmission”.

TCP Port numbers reused

Set when the SYN flag is set (not SYN+ACK), we have an existing conversation using the same addresses and ports, and the sequencue number is different than the existing conversation’s initial sequence number.

TCP Previous segment not captured

Set when the current sequence number is greater than the next expected sequence number.

TCP Spurious Retransmission

Checks for a retransmission based on analysis data in the reverse direction. Set when all of the following are true:

  • The SYN or FIN flag is set.
  • This is not a keepalive packet.
  • The segment length is greater than zero.
  • Data for this flow has been acknowledged. That is, the last-seen acknowledgement number has been set.
  • The next sequence number is less than or equal to the last-seen acknowledgement number.

Supersedes “Retransmission”.

TCP Retransmission

Set when all of the following are true:

  • This is not a keepalive packet.
  • In the forward direction, the segment length is greater than zero or the SYN or FIN flag is set.
  • The next expected sequence number is greater than the current sequence number.

TCP Window Full

Set when the segment size is non-zero, we know the window size in the reverse direction, and our segment size exceeds the window size in the reverse direction.

TCP Window Update

Set when the all of the following are true:

  • The segment size is zero.
  • The window size is non-zero and not equal to the last-seen window size.
  • The sequence number is equal to the next expected sequence number.
  • The acknowledgement number is equal to the last-seen acknowledgement number.
  • None of SYN, FIN, or RST are set.

TCP ZeroWindow

Set when the window size is zero and non of SYN, FIN, or RST are set.

TCP ZeroWindowProbe

Set when the sequence number is equal to the next expected sequence number, the segment size is one, and last-seen window size in the reverse direction was zero.

TCP ZeroWindowProbeAck

Set when the all of the following are true:

  • The segment size is zero.
  • The window size is zero.
  • The sequence number is equal to the next expected sequence number.
  • The acknowledgement number is equal to the last-seen acknowledgement number.
  • The last-seen packet in the reverse direction was a zero window probe.

Supersedes “TCP Dup ACK”.

7.6. Time Stamps

Time stamps, their precisions and all that can be quite confusing. This section will provide you with information about what’s going on while Wireshark processes time stamps.

While packets are captured, each packet is time stamped as it comes in. These time stamps will be saved to the capture file, so they also will be available for (later) analysis.

So where do these time stamps come from? While capturing, Wireshark gets the time stamps from the libpcap (WinPcap) library, which in turn gets them from the operating system kernel. If the capture data is loaded from a capture file, Wireshark obviously gets the data from that file.

7.6.1. Wireshark internals

The internal format that Wireshark uses to keep a packet time stamp consists of the date (in days since 1.1.1970) and the time of day (in nanoseconds since midnight). You can adjust the way Wireshark displays the time stamp data in the packet list, see the “Time Display Format” item in the Section 3.7, “The “View” Menu” for details.

While reading or writing capture files, Wireshark converts the time stamp data between the capture file format and the internal format as required.

While capturing, Wireshark uses the libpcap (WinPcap) capture library which supports microsecond resolution. Unless you are working with specialized capturing hardware, this resolution should be adequate.

7.6.2. Capture file formats

Every capture file format that Wireshark knows supports time stamps. The time stamp precision supported by a specific capture file format differs widely and varies from one second “0” to one nanosecond “0.123456789”. Most file formats store the time stamps with a fixed precision (e.g. microseconds), while some file formats are even capable of storing the time stamp precision itself (whatever the benefit may be).

The common libpcap capture file format that is used by Wireshark (and a lot of other tools) supports a fixed microsecond resolution “0.123456” only.

Writing data into a capture file format that doesn’t provide the capability to store the actual precision will lead to loss of information. For example, if you load a capture file with nanosecond resolution and store the capture data in a libpcap file (with microsecond resolution) Wireshark obviously must reduce the precision from nanosecond to microsecond.

7.6.3. Accuracy

People often ask “Which time stamp accuracy is provided by Wireshark?”. Well, Wireshark doesn’t create any time stamps itself but simply gets them from “somewhere else” and displays them. So accuracy will depend on the capture system (operating system, performance, etc) that you use. Because of this, the above question is difficult to answer in a general way.

[Note] Note

USB connected network adapters often provide a very bad time stamp accuracy. The incoming packets have to take “a long and winding road” to travel through the USB cable until they actually reach the kernel. As the incoming packets are time stamped when they are processed by the kernel, this time stamping mechanism becomes very inaccurate.

Don’t use USB connected NICs when you need precise time stamp accuracy.

7.7. Time Zones

If you travel across the planet, time zones can be confusing. If you get a capture file from somewhere around the world time zones can even be a lot more confusing ;-)

First of all, there are two reasons why you may not need to think about time zones at all:

  • You are only interested in the time differences between the packet time stamps and don’t need to know the exact date and time of the captured packets (which is often the case).
  • You don’t get capture files from different time zones than your own, so there are simply no time zone problems. For example, everyone in your team is working in the same time zone as yourself.

Further time zone and DST information can be found at http://wwp.greenwichmeantime.com/ and http://www.timeanddate.com/worldclock/.

7.7.1. Set your computer’s time correctly!

If you work with people around the world it’s very helpful to set your computer’s time and time zone right.

You should set your computers time and time zone in the correct sequence:

  1. Set your time zone to your current location
  2. Set your computer’s clock to the local time

This way you will tell your computer both the local time and also the time offset to UTC. Many organizations simply set the time zone on their servers and networking gear to UTC in order to make coordination and troubleshooting easier.

[Tip] Tip

If you travel around the world, it’s an often made mistake to adjust the hours of your computer clock to the local time. Don’t adjust the hours but your time zone setting instead! For your computer, the time is essentially the same as before, you are simply in a different time zone with a different local time.

You can use the Network Time Protocol (NTP) to automatically adjust your computer to the correct time, by synchronizing it to Internet NTP clock servers. NTP clients are available for all operating systems that Wireshark supports (and for a lot more), for examples see http://www.ntp.org/.

7.7.2. Wireshark and Time Zones

So what’s the relationship between Wireshark and time zones anyway?

Wireshark’s native capture file format (libpcap format), and some other capture file formats, such as the Windows Sniffer, EtherPeek, AiroPeek, and Sun snoop formats, save the arrival time of packets as UTC values. UN*X systems, and “Windows NT based” systems represent time internally as UTC. When Wireshark is capturing, no conversion is necessary. However, if the system time zone is not set correctly, the system’s UTC time might not be correctly set even if the system clock appears to display correct local time. When capturing, WinPcap has to convert the time to UTC before supplying it to Wireshark. If the system’s time zone is not set correctly, that conversion will not be done correctly.

Other capture file formats, such as the Microsoft Network Monitor, DOS-based Sniffer, and Network Instruments Observer formats, save the arrival time of packets as local time values.

Internally to Wireshark, time stamps are represented in UTC. This means that when reading capture files that save the arrival time of packets as local time values, Wireshark must convert those local time values to UTC values.

Wireshark in turn will display the time stamps always in local time. The displaying computer will convert them from UTC to local time and displays this (local) time. For capture files saving the arrival time of packets as UTC values, this means that the arrival time will be displayed as the local time in your time zone, which might not be the same as the arrival time in the time zone in which the packet was captured. For capture files saving the arrival time of packets as local time values, the conversion to UTC will be done using your time zone’s offset from UTC and DST rules, which means the conversion will not be done correctly; the conversion back to local time for display might undo this correctly, in which case the arrival time will be displayed as the arrival time in which the packet was captured.

Table 7.2. Time zone examples for UTC arrival times (without DST)

  Los Angeles New York Madrid London Berlin Tokyo

Capture File (UTC)

10:00

10:00

10:00

10:00

10:00

10:00

Local Offset to UTC

-8

-5

-1

0

+1

+9

Displayed Time (Local Time)

02:00

05:00

09:00

10:00

11:00

19:00


For example let’s assume that someone in Los Angeles captured a packet with Wireshark at exactly 2 o’clock local time and sends you this capture file. The capture file’s time stamp will be represented in UTC as 10 o’clock. You are located in Berlin and will see 11 o’clock on your Wireshark display.

Now you have a phone call, video conference or Internet meeting with that one to talk about that capture file. As you are both looking at the displayed time on your local computers, the one in Los Angeles still sees 2 o’clock but you in Berlin will see 11 o’clock. The time displays are different as both Wireshark displays will show the (different) local times at the same point in time.

Conclusion: You may not bother about the date/time of the time stamp you currently look at unless you must make sure that the date/time is as expected. So, if you get a capture file from a different time zone and/or DST, you’ll have to find out the time zone/DST difference between the two local times and “mentally adjust” the time stamps accordingly. In any case, make sure that every computer in question has the correct time and time zone setting.

7.8. Packet Reassembly

7.8.1. What is it?

Network protocols often need to transport large chunks of data which are complete in themselves, e.g. when transferring a file. The underlying protocol might not be able to handle that chunk size (e.g. limitation of the network packet size), or is stream-based like TCP, which doesn’t know data chunks at all.

In that case the network protocol has to handle the chunk boundaries itself and (if required) spread the data over multiple packets. It obviously also needs a mechanism to determine the chunk boundaries on the receiving side.

Wireshark calls this mechanism reassembly, although a specific protocol specification might use a different term for this (e.g. desegmentation, defragmentation, etc).

7.8.2. How Wireshark handles it

For some of the network protocols Wireshark knows of, a mechanism is implemented to find, decode and display these chunks of data. Wireshark will try to find the corresponding packets of this chunk, and will show the combined data as additional pages in the “Packet Bytes” pane (for information about this pane. See Section 3.19, “The “Packet Bytes” Pane”).

Figure 7.6. The “Packet Bytes” pane with a reassembled tab

ws bytes pane tabs

Reassembly might take place at several protocol layers, so it’s possible that multiple tabs in the “Packet Bytes” pane appear.

[Note] Note

You will find the reassembled data in the last packet of the chunk.

For example, in a HTTP GET response, the requested data (e.g. an HTML page) is returned. Wireshark will show the hex dump of the data in a new tab “Uncompressed entity body” in the “Packet Bytes” pane.

Reassembly is enabled in the preferences by default but can be disabled in the preferences for the protocol in question. Enabling or disabling reassembly settings for a protocol typically requires two things:

  1. The lower level protocol (e.g., TCP) must support reassembly. Often this reassembly can be enabled or disabled via the protocol preferences.
  2. The higher level protocol (e.g., HTTP) must use the reassembly mechanism to reassemble fragmented protocol data. This too can often be enabled or disabled via the protocol preferences.

The tooltip of the higher level protocol setting will notify you if and which lower level protocol setting also has to be considered.

7.8.3. TCP Reassembly

Protocols such as HTTP or TLS are likely to span multiple TCP segments. The TCP protocol preference “Allow subdissector to reassemble TCP streams” (enabled by default) makes it possible for Wireshark to collect a contiguous sequence of TCP segments and hand them over to the higher level protocol (for example, to reconstruct a full HTTP message). All but the final segment will be marked with “[TCP segment of a reassembled PDU]” in the packet list.

Disable this preference to reduce memory and processing overhead if you are only interested in TCP sequence number analysis (Section 7.5, “TCP Analysis”). Keep in mind, though, that higher level protocols might be wrongly dissected. For example, HTTP messages could be shown as “Continuation” and TLS records could be shown as “Ignored Unknown Record”. Such results can also be observed if you start capturing while a TCP connection was already started or when TCP segments are lost or delivered out-of-order.

To reassemble of out-of-order TCP segments, the TCP protocol preference “Reassemble out-of-order segments” (currently disabled by default) must be enabled in addition to the previous preference. If all packets are received in-order, this preference will not have any effect. Otherwise (if missing segments are encountered while sequentially processing a packet capture), it is assumes that the new and missing segments belong to the same PDU. Caveats:

  • Lost packets are assumed to be received out-of-order or retransmitted later. Applications usually retransmit segments until these are acknowledged, but if the packet capture drops packets, then Wireshark will not be able to reconstruct the TCP stream. In such cases, you can try to disable this preference and hopefully have a partial dissection instead of seeing just “[TCP segment of a reassembled PDU]” for every TCP segment.
  • When doing a capture in monitor mode (IEEE 802.11), packets are more likely to get lost due to signal reception issues. In that case it is recommended to disable the option.
  • If the new and missing segments are in fact part of different PDUs, then processing is currently delayed until no more segments are missing, even if the begin of the missing segments completed a PDU. For example, assume six segments forming two PDUs ABC and DEF. When received as ABECDF, an application can start processing the first PDU after receiving ABEC. Wireshark however requires the missing segment D to be received as well. This issue will be addressed in the future.
  • In the GUI and during a two-pass dissection (tshark -2), the previous scenario will display both PDUs in the packet with last segment (F) rather than displaying it in the first packet that has the final missing segment of a PDU. This issue will be addressed in the future.
  • When enabled, fields such as the SMB “Time from request” (smb.time) might be smaller if the request follows other out-of-order segments (this reflects application behavior). If the previous scenario however occurs, then the time of the request is based on the frame where all missing segments are received.

Regardless of the setting of these two reassembly-related preferences, you can always use the “Follow TCP Stream” option (Section 7.2, “Following Protocol Streams”) which displays segments in the expected order.

7.9. Name Resolution

Name resolution tries to convert some of the numerical address values into a human readable format. There are two possible ways to do these conversions, depending on the resolution to be done: calling system/network services (like the gethostname() function) and/or resolve from Wireshark specific configuration files. For details about the configuration files Wireshark uses for name resolution and alike, see Appendix B, Files and Folders.

The name resolution feature can be enabled individually for the protocol layers listed in the following sections.

7.9.1. Name Resolution drawbacks

Name resolution can be invaluable while working with Wireshark and may even save you hours of work. Unfortunately, it also has its drawbacks.

  • Name resolution will often fail. The name to be resolved might simply be unknown by the name servers asked, or the servers are just not available and the name is also not found in Wireshark’s configuration files.
  • The resolved names are not stored in the capture file or somewhere else. So the resolved names might not be available if you open the capture file later or on a different machine. Each time you open a capture file it may look “slightly different” simply because you can’t connect to the name server (which you could connect to before).
  • DNS may add additional packets to your capture file. You may see packets to/from your machine in your capture file, which are caused by name resolution network services of the machine Wireshark captures from.
  • Resolved DNS names are cached by Wireshark. This is required for acceptable performance. However, if the name resolution information should change while Wireshark is running, Wireshark won’t notice a change in the name resolution information once it gets cached. If this information changes while Wireshark is running, e.g. a new DHCP lease takes effect, Wireshark won’t notice it.

Name resolution in the packet list is done while the list is filled. If a name can be resolved after a packet is added to the list, its former entry won’t be changed. As the name resolution results are cached, you can use ViewReload to rebuild the packet list with the correctly resolved names. However, this isn’t possible while a capture is in progress.

7.9.2. Ethernet name resolution (MAC layer)

Try to resolve an Ethernet MAC address (e.g. 00:09:5b:01:02:03) to something more “human readable”.

ARP name resolution (system service): Wireshark will ask the operating system to convert an Ethernet address to the corresponding IP address (e.g. 00:09:5b:01:02:03 → 192.168.0.1).

Ethernet codes (ethers file): If the ARP name resolution failed, Wireshark tries to convert the Ethernet address to a known device name, which has been assigned by the user using an ethers file (e.g. 00:09:5b:01:02:03 → homerouter).

Ethernet manufacturer codes (manuf file): If neither ARP or ethers returns a result, Wireshark tries to convert the first 3 bytes of an ethernet address to an abbreviated manufacturer name, which has been assigned by the IEEE (e.g. 00:09:5b:01:02:03 → Netgear_01:02:03).

7.9.3. IP name resolution (network layer)

Try to resolve an IP address (e.g. 216.239.37.99) to something more “human readable”.

DNS name resolution (system/library service): Wireshark will use a name resolver to convert an IP address to the hostname associated with it (e.g. 216.239.37.99 → www.1.google.com).

DNS name resolution can generally be performed synchronously or asynchronously. Both mechanisms can be used to convert an IP address to some human readable (domain) name. A system call like gethostname() will try to convert the address to a name. To do this, it will first ask the systems hosts file (e.g. /etc/hosts) if it finds a matching entry. If that fails, it will ask the configured DNS server(s) about the name.

So the real difference between synchronous DNS and asynchronous DNS comes when the system has to wait for the DNS server about a name resolution. The system call gethostname() will wait until a name is resolved or an error occurs. If the DNS server is unavailable, this might take quite a while (several seconds).

[Warning] Warning

To provide acceptable performance Wireshark depends on an asynchronous DNS library to do name resolution. If one isn’t available during compilation the feature will be unavailable.

The asynchronous DNS service works a bit differently. It will also ask the DNS server, but it won’t wait for the answer. It will just return to Wireshark in a very short amount of time. The actual (and the following) address fields won’t show the resolved name until the DNS server returns an answer. As mentioned above, the values get cached, so you can use ViewReload to “update” these fields to show the resolved values.

hosts name resolution (hosts file): If DNS name resolution failed, Wireshark will try to convert an IP address to the hostname associated with it, using a hosts file provided by the user (e.g. 216.239.37.99 → www.google.com).

7.9.4. TCP/UDP port name resolution (transport layer)

Try to resolve a TCP/UDP port (e.g. 80) to something more “human readable”.

TCP/UDP port conversion (system service): Wireshark will ask the operating system to convert a TCP or UDP port to its well known name (e.g. 80 → http).

7.9.5. VLAN ID resolution

To get a descriptive name for a VLAN tag ID a vlans file can be used.

7.9.6. SS7 point code resolution

To get a node name for a SS7 point code a ss7pcs file can be used.

7.10. Checksums

Several network protocols use checksums to ensure data integrity. Applying checksums as described here is also known as redundancy checking.

7.10.1. Wireshark checksum validation

Wireshark will validate the checksums of many protocols, e.g. IP, TCP, UDP, etc.

It will do the same calculation as a “normal receiver” would do, and shows the checksum fields in the packet details with a comment, e.g. [correct] or [invalid, must be 0x12345678].

Checksum validation can be switched off for various protocols in the Wireshark protocol preferences, e.g. to (very slightly) increase performance.

If the checksum validation is enabled and it detected an invalid checksum, features like packet reassembly won’t be processed. This is avoided as incorrect connection data could “confuse” the internal database.

7.10.2. Checksum offloading

The checksum calculation might be done by the network driver, protocol driver or even in hardware.

For example: The Ethernet transmitting hardware calculates the Ethernet CRC32 checksum and the receiving hardware validates this checksum. If the received checksum is wrong Wireshark won’t even see the packet, as the Ethernet hardware internally throws away the packet.

Higher level checksums are “traditionally” calculated by the protocol implementation and the completed packet is then handed over to the hardware.

Recent network hardware can perform advanced features such as IP checksum calculation, also known as checksum offloading. The network driver won’t calculate the checksum itself but will simply hand over an empty (zero or garbage filled) checksum field to the hardware.

[Note] Note

Checksum offloading often causes confusion as the network packets to be transmitted are handed over to Wireshark before the checksums are actually calculated. Wireshark gets these “empty” checksums and displays them as invalid, even though the packets will contain valid checksums when they leave the network hardware later.

Checksum offloading can be confusing and having a lot of [invalid] messages on the screen can be quite annoying. As mentioned above, invalid checksums may lead to unreassembled packets, making the analysis of the packet data much harder.

You can do two things to avoid this checksum offloading problem:

  • Turn off the checksum offloading in the network driver, if this option is available.
  • Turn off checksum validation of the specific protocol in the Wireshark preferences. Recent releases of Wireshark disable checksum validation by default due to the prevalance of offloading in modern hardware and operating systems.

Chapter 8. Statistics

8.1. Introduction

Wireshark provides a wide range of network statistics which can be accessed via the Statistics menu.

These statistics range from general information about the loaded capture file (like the number of captured packets), to statistics about specific protocols (e.g. statistics about the number of HTTP requests and responses captured).

  • General statistics:

    • Capture File Properties about the capture file.
    • Protocol Hierarchy of the captured packets.
    • Conversations e.g. traffic between specific IP addresses.
    • Endpoints e.g. traffic to and from an IP addresses.
    • IO Graphs visualizing the number of packets (or similar) in time.
  • Protocol specific statistics:

    • Service Response Time between request and response of some protocols.
    • Various other protocol specific statistics.
[Note] Note

The protocol specific statistics require detailed knowledge about the specific protocol. Unless you are familiar with that protocol, statistics about it will be pretty hard to understand.

Wireshark has many other statistics windows that display detailed information about specific protocols and might be described in a later version of this document.

Some of these statistics are described at https://wiki.wireshark.org/Statistics.

8.2. The “Capture File Properties” Window

General statistics about the current capture file.

Figure 8.1. The “Capture File Properties” window

ws stats summary

  • File: general information about the capture file.
  • Time: the timestamps when the first and the last packet were captured (and the time between them).
  • Capture: information from the time when the capture was done (only available if the packet data was captured from the network and not loaded from a file).
  • Interface: information about the capture interface.
  • Statistics: some statistics of the network traffic seen. If a display filter is set, you will see values in the Captured column, and if any packages are marked, you will see values in the Marked column. The values in the Captured column will remain the same as before, while the values in the Displayed column will reflect the values corresponding to the packets shown in the display. The values in the Marked column will reflect the values corresponding to the marked packages.

8.3. Resolved Addresses

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.4. The “Protocol Hierarchy” Window

The protocol hierarchy of the captured packets.

Figure 8.2. The “Protocol Hierarchy” Window

ws stats hierarchy

This is a tree of all the protocols in the capture. Each row contains the statistical values of one protocol. Two of the columns (Percent Packets and Percent Bytes) serve double duty as bar graphs. If a display filter is set it will be shown at the bottom.

The Copy button will let you copy the window contents as CSV or YAML.

Protocol hierarchy columns

Protocol
This protocol’s name
Percent Packets
The percentage of protocol packets relative to all packets in the capture
Packets
The total number of packets of this protocol
Percent Bytes
The percentage of protocol bytes relative to the total bytes in the capture
Bytes
The total number of bytes of this protocol
Bits/s
The bandwidth of this protocol relative to the capture time
End Packets
The absolute number of packets of this protocol where it was the highest protocol in the stack (last dissected)
End Bytes
The absolute number of bytes of this protocol where it was the highest protocol in the stack (last dissected)
End Bits/s
The bandwidth of this protocol relative to the capture time where was the highest protocol in the stack (last dissected)

Packets usually contain multiple protocols. As a result more than one protocol will be counted for each packet. Example: In the screenshot IP has 99.9% and TCP 98.5% (which is together much more than 100%).

Protocol layers can consist of packets that won’t contain any higher layer protocol, so the sum of all higher layer packets may not sum up to the protocols packet count. Example: In the screenshot TCP has 98.5% but the sum of the subprotocols (TLS, HTTP, etc) is much less. This can be caused by continuation frames, TCP protocol overhead, and other undissected data.

A single packet can contain the same protocol more than once. In this case, the protocol is counted more than once. For example ICMP replies and many tunneling protocols will carry more than one IP header.

8.5. Conversations

A network conversation is the traffic between two specific endpoints. For example, an IP conversation is all the traffic between two IP addresses. The description of the known endpoint types can be found in Section 8.6, “Endpoints”.

8.5.1. The “Conversations” Window

The conversations window is similar to the endpoint Window. See Section 8.6.1, “The “Endpoints” Window” for a description of their common features. Along with addresses, packet counters, and byte counters the conversation window adds four columns: the start time of the conversation (“Rel Start”) or (“Abs Start”), the duration of the conversation in seconds, and the average bits (not bytes) per second in each direction. A timeline graph is also drawn across the “Rel Start” / “Abs Start” and “Duration” columns.

Figure 8.3. The “Conversations” window

ws stats conversations

Each row in the list shows the statistical values for exactly one conversation.

Name resolution will be done if selected in the window and if it is active for the specific protocol layer (MAC layer for the selected Ethernet endpoints page). Limit to display filter will only show conversations matching the current display filter. Absolute start time switches the start time column between relative (“Rel Start”) and absolute (“Abs Start”) times. Relative start times match the “Seconds Since Beginning of Capture” time display format in the packet list and absolute start times match the “Time of Day” display format.

The Copy button will copy the list values to the clipboard in CSV (Comma Separated Values) or YAML format. The Follow Stream…​ button will show the stream contents as described in Figure 7.1, “The “Follow TCP Stream” dialog box” dialog. The Graph…​ button will show a graph as described in Section 8.8, “The “I/O Graph” Window”.

Conversation Types lets you choose which traffic type tabs are shown. See Section 8.6, “Endpoints” for a list of endpoint types. The enabled types are saved in your profile settings.

[Tip] Tip

This window will be updated frequently so it will be useful even if you open it before (or while) you are doing a live capture.

8.6. Endpoints

A network endpoint is the logical endpoint of separate protocol traffic of a specific protocol layer. The endpoint statistics of Wireshark will take the following endpoints into account:

[Tip] Tip

If you are looking for a feature other network tools call a hostlist, here is the right place to look. The list of Ethernet or IP endpoints is usually what you’re looking for.

Endpoint and Conversation types

Bluetooth
A MAC-48 address similar to Ethernet.
Ethernet
Identical to the Ethernet device’s MAC-48 identifier.
Fibre Channel
A MAC-48 address similar to Ethernet.
IEEE 802.11
A MAC-48 address similar to Ethernet.
FDDI
Identical to the FDDI MAC-48 address.
IPv4
Identical to the 32-bit IPv4 address.
IPv6
Identical to the 128-bit IPv6 address.
IPX
A concatenation of a 32 bit network number and 48 bit node address, by default the Ethernet interface’s MAC-48 address.
JXTA
A 160 bit SHA-1 URN.
NCP
Similar to IPX.
RSVP
A combination of varios RSVP session attributes and IPv4 addresses.
SCTP
A combination of the host IP addresses (plural) and the SCTP port used. So different SCTP ports on the same IP address are different SCTP endpoints, but the same SCTP port on different IP addresses of the same host are still the same endpoint.
TCP
A combination of the IP address and the TCP port used. Different TCP ports on the same IP address are different TCP endpoints.
Token Ring
Identical to the Token Ring MAC-48 address.
UDP
A combination of the IP address and the UDP port used, so different UDP ports on the same IP address are different UDP endpoints.
USB
Identical to the 7-bit USB address.
[Note] Broadcast and multicast endpoints

Broadcast and multicast traffic will be shown separately as additional endpoints. Of course, as these aren’t physical endpoints the real traffic will be received by some or all of the listed unicast endpoints.

8.6.1. The “Endpoints” Window

This window shows statistics about the endpoints captured.

Figure 8.4. The “Endpoints” window

ws stats endpoints

For each supported protocol, a tab is shown in this window. Each tab label shows the number of endpoints captured (e.g. the tab label “Ethernet · 4” tells you that four ethernet endpoints have been captured). If no endpoints of a specific protocol were captured, the tab label will be greyed out (although the related page can still be selected).

Each row in the list shows the statistical values for exactly one endpoint.

Name resolution will be done if selected in the window and if it is active for the specific protocol layer (MAC layer for the selected Ethernet endpoints page). Limit to display filter will only show conversations matching the current display filter. Note that in this example we have MaxMind DB configured which gives us extra geographic columns. See Section 11.10, “MaxMind Database Paths” for more information.

The Copy button will copy the list values to the clipboard in CSV (Comma Separated Values) or YAML format.

Endpoint Types lets you choose which traffic type tabs are shown. See Section 8.6, “Endpoints” above for a list of endpoint types. The enabled types are saved in your profile settings.

[Tip] Tip

This window will be updated frequently, so it will be useful even if you open it before (or while) you are doing a live capture.

8.7. Packet Lengths

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.8. The “I/O Graph” Window

User configurable graph of the captured network packets.

You can define up to five differently colored graphs.

Figure 8.5. The “IO Graphs” window

ws stats iographs

The user can configure the following things:

  • Graphs

    • Graph 1-5: enable the specific graph 1-5 (only graph 1 is enabled by default)
    • Color: the color of the graph (cannot be changed)
    • Filter: a display filter for this graph (only the packets that pass this filter will be taken into account for this graph)
    • Style: the style of the graph (Line/Impulse/FBar/Dot)
  • X Axis

    • Tick interval: an interval in x direction lasts (10/1 minutes or 10/1/0.1/0.01/0.001 seconds)
    • Pixels per tick: use 10/5/2/1 pixels per tick interval
    • View as time of day: option to view x direction labels as time of day instead of seconds or minutes since beginning of capture
  • Y Axis

    • Unit: the unit for the y direction (Packets/Tick, Bytes/Tick, Bits/Tick, Advanced…​) [XXX - describe the Advanced feature.]
    • Scale: the scale for the y unit (Logarithmic,Auto,10,20,50,100,200,500,…​)

The Save button will save the currently displayed portion of the graph as one of various file formats.

The Copy button will copy values from selected graphs to the clipboard in CSV (Comma Separated Values) format.

[Tip] Tip

Click in the graph to select the first package in the selected interval.

8.9. Service Response Time

The service response time is the time between a request and the corresponding response. This information is available for many protocols.

Service response time statistics are currently available for the following protocols:

  • DCE-RPC
  • Fibre Channel
  • H.225 RAS
  • LDAP
  • LTE MAC
  • MGCP
  • ONC-RPC
  • SMB

As an example, the DCE-RPC service response time is described in more detail.

[Note] Note

The other Service Response Time windows will work the same way (or only slightly different) compared to the following description.

8.9.1. The “Service Response Time DCE-RPC” Window

The service response time of DCE-RPC is the time between the request and the corresponding response.

First of all, you have to select the DCE-RPC interface:

Figure 8.6. The “Compute DCE-RPC statistics” window

ws stats srt dcerpc filter

You can optionally set a display filter, to reduce the amount of packets.

Figure 8.7. The “DCE-RPC Statistic for …​” window

ws stats srt dcerpc

Each row corresponds to a method of the interface selected (so the EPM interface in version 3 has 7 methods). For each method the number of calls, and the statistics of the SRT time is calculated.

8.10. DHCP (BOOTP) Statistics

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.11. ONC-RPC Programs

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.15. Collectd

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.17. Flow Graph

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.18. HART-IP

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.19. HPFEEDS

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.20. HTTP Statistics

8.20.1. HTTP Packet Counter

Statistics for HTTP request types and response codes.

8.20.2. HTTP Requests

HTTP statistics based on the host and URI.

8.20.3. HTTP Load Distribution

HTTP request and response statistics based on the server address and host.

8.20.4. HTTP Request Sequences

HTTP Request Sequences uses HTTP’s Referer and Location headers to sequence a capture’s HTTP requests as a tree. This enables analysts to see how one HTTP request leads to the next.

Figure 8.8. The “HTTP Request Sequences” window

ws stats http requestsequences

8.22. Sametime

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.23. TCP Stream Graphs

Show different visual representations of the TCP streams in a capture.

Time Sequence (Stevens)
This is a simple graph of the TCP sequence number over time, similar to the ones used in Richard Stevens’ “TCP/IP Illustrated” series of books.
Time Sequence (tcptrace)
Shows TCP metrics similar to the tcptrace utility, including forward segments, acknowledgements, selective acknowledgements, reverse window sizes, and zero windows.
Throughput
Average throughput and goodput.
Round Trip Time
Round trip time vs time or sequence number. RTT is based on the acknowledgement timestamp corresponding to a particular segment.
Window Scaling
Window size and outstanding bytes.

8.24. UDP Multicast Graphs

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.26. IPv4 Statistics

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

8.27. IPv6 Statistics

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Chapter 9. Telephony

9.1. Introduction

Wireshark provides a wide range of telephony related network statistics which can be accessed via the Telephony menu.

These statistics range from specific signaling protocols, to analysis of signaling and media flows. If encoded in a compatible encoding the media flow can even be played.

The protocol specific statistics windows display detailed information of specific protocols and might be described in a later version of this document.

Some of these statistics are described at the https://wiki.wireshark.org/Statistics pages.

9.2. VoIP Calls

The VoIP Calls window shows a list of all detected VoIP calls in the captured traffic. It finds calls by their signaling.

More details can be found on the https://wiki.wireshark.org/VoIP_calls page.

9.5. IAX2 Stream Analysis

The “IAX2 Stream Analysis” dialog shows statistics for the forward and reverse streams of a selected IAX2 call along with a graph.

9.6. ISUP Messages

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.7. LTE

9.7.1. LTE MAC Traffic Statistics

Statistics of the captured LTE MAC traffic. This window will summarize the LTE MAC traffic found in the capture.

Figure 9.1. The “LTE MAC Traffic Statistics” window

ws stats lte mac traffic

The top pane shows statistics for common channels. Each row in the middle pane shows statistical highlights for exactly one UE/C-RNTI. In the lower pane, you can see the for the currently selected UE/C-RNTI the traffic broken down by individual channel.

9.7.2. LTE RLC Graph

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.7.3. LTE RLC Traffic Statistics

Statistics of the captured LTE RLC traffic. This window will summarize the LTE RLC traffic found in the capture.

Figure 9.2. The “LTE RLC Traffic Statistics” window

ws stats lte rlc traffic

At the top, the check-box allows this window to include RLC PDUs found within MAC PDUs or not. This will affect both the PDUs counted as well as the display filters generated (see below).

The upper list shows summaries of each active UE. Each row in the lower list shows statistical highlights for individual channels within the selected UE.

The lower part of the windows allows display filters to be generated and set for the selected channel. Note that in the case of Acknowledged Mode channels, if a single direction is chosen, the generated filter will show data in that direction and control PDUs in the opposite direction.

9.10. RTP Analysis

The RTP analysis function takes the selected RTP stream (and the reverse stream, if possible) and generates a list of statistics on it.

Figure 9.3. The “RTP Stream Analysis” window

ws tel rtpstream analysis

Starting with basic data as packet number and sequence number, further statistics are created based on arrival time, delay, jitter, packet size, etc.

Besides the per packet statistics, the lower pane shows the overall statistics, with minimums and maximums for delta, jitter and clock skew. Also an indication of lost packets is included.

The RTP Stream Analysis window further provides the option to save the RTP payload (as raw data or, if in a PCM encoding, in an Audio file). Other options a to export and plot various statistics on the RTP streams.

The RTP Player window lets you play back RTP audio data. In order to use this feature your version of Wireshark must support audio and the codecs used by each RTP stream.

More details can be found on the https://wiki.wireshark.org/VoIP_calls page.

9.13. SMPP Operations

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.14. UCP Messages

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.16. SIP Flows

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.17. SIP Statistics

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

9.18. WAP-WSP Packet Counter

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Chapter 10. Wireless

10.1. Introduction

The Wireless menu provides access to statistics related to wireless traffic.

10.2. Bluetooth ATT Server Attributes

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

10.3. Bluetooth Devices

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

10.4. Bluetooth HCI Summary

Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

10.5. WLAN Traffic

Statistics about captured WLAN traffic. This can be found under the Wireless menu and summarizes the wireless network traffic found in the capture. Probe requests will be merged into an existing network if the SSID matches.

Figure 10.1. The “WLAN Traffic Statistics” window

ws stats wlan traffic

Each row in the list shows the statistical values for exactly one wireless network.

Name resolution will be done if selected in the window and if it is active for the MAC layer.

Only show existing networks will exclude probe requests with a SSID not matching any network from the list.

The Copy button will copy the list values to the clipboard in CSV (Comma Separated Values) format.

[Tip] Tip

This window will be updated frequently, so it will be useful, even if you open it before (or while) you are doing a live capture.

Chapter 11. Customizing Wireshark

11.1. Introduction

Wireshark’s default behaviour will usually suit your needs pretty well. However, as you become more familiar with Wireshark, it can be customized in various ways to suit your needs even better. In this chapter we explore:

  • How to start Wireshark with command line parameters
  • How to colorize the packet list
  • How to control protocol dissection
  • How to use the various preference settings

11.2. Start Wireshark from the command line

You can start Wireshark from the command line, but it can also be started from most Window managers as well. In this section we will look at starting it from the command line.

Wireshark supports a large number of command line parameters. To see what they are, simply enter the command wireshark -h and the help information shown in Example 11.1, “Help information available from Wireshark” (or something similar) should be printed.

Example 11.1. Help information available from Wireshark

Wireshark 2.1.0 (v2.1.0rc0-502-g328fbc0 from master)
Interactively dump and analyze network traffic.
See https://www.wireshark.org for more information.

Usage: wireshark [options] ... [ <infile> ]

Capture interface:
  -i <interface>           name or idx of interface (def: first non-loopback)
  -f <capfilter|predef:>   packet filter in libpcap filter syntax or
                           predef:filtername - predefined filtername from GUI
  -s <snaplen>             packet snapshot length (def: 262144)
  -p                       don’t capture in promiscuous mode
  -k                       start capturing immediately (def: do nothing)
  -S                       update packet display when new packets are captured
  -l                       turn on automatic scrolling while -S is in use
  -I                       capture in monitor mode, if available
  -B <buffer size>         size of kernel buffer (def: 2MB)
  -y <link type>           link layer type (def: first appropriate)
  --time-stamp-type <type> timestamp method for interface
  -D                       print list of interfaces and exit
  -L                       print list of link-layer types of iface and exit
  --list-time-stamp-types  print list of timestamp types for iface and exit

Capture stop conditions:
  -c <packet count>        stop after n packets (def: infinite)
  -a <autostop cond.> ...  duration:NUM - stop after NUM seconds
                           filesize:NUM - stop this file after NUM KB
                              files:NUM - stop after NUM files
Capture output:
  -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
                           filesize:NUM - switch to next file after NUM KB
                              files:NUM - ringbuffer: replace after NUM files
RPCAP options:
  -A <user>:<password>     use RPCAP password authentication
Input file:
  -r <infile>              set the filename to read from (no pipes or stdin!)

Processing:
  -R <read filter>         packet filter in Wireshark display filter syntax
  -n                       disable all name resolutions (def: all enabled)
  -N <name resolve flags>  enable specific name resolution(s): "mnNtdv"
  -d <layer_type>==<selector>,<decode_as_protocol> ...
                           "Decode As”, see the man page for details
                           Example: tcp.port==8888,http
  --disable-protocol <proto_name>
                           disable dissection of proto_name
  --enable-heuristic <short_name>
                           enable dissection of heuristic protocol
  --disable-heuristic <short_name>
                           disable dissection of heuristic protocol

User interface:
  -C <config profile>      start with specified configuration profile
  -Y <display filter>      start with the given display filter
  -g <packet number>       go to specified packet number after "-r"
  -J <jump filter>         jump to the first packet matching the (display)
                           filter
  -j                       search backwards for a matching packet after "-J"
  -m <font>                set the font name used for most text
  -t a|ad|d|dd|e|r|u|ud    output format of time stamps (def: r: rel. to first)
  -u s|hms                 output format of seconds (def: s: seconds)
  -X <key>:<value>         eXtension options, see man page for details
  -z <statistics>          show various statistics, see man page for details

Output:
  -w <outfile|->           set the output filename (or '-' for stdout)

Miscellaneous:
  -h                       display this help and exit
  -v                       display version info and exit
  -P <key>:<path>          persconf:path - personal configuration files
                           persdata:path - personal data files
  -o <name>:<value> ...    override preference or recent setting
  -K <keytab>              keytab file to use for kerberos decryption

We will examine each of the command line options in turn.

The first thing to notice is that issuing the command wireshark by itself will bring up Wireshark. However, you can include as many of the command line parameters as you like. Their meanings are as follows ( in alphabetical order ):

-a <capture autostop condition>

Specify a criterion that specifies when Wireshark is to stop writing to a capture file. The criterion is of the form test:value, where test is one of:

duration:value
Stop writing to a capture file after value of seconds have elapsed.
filesize:value
Stop writing to a capture file after it reaches a size of value kilobytes (where a kilobyte is 1000 bytes, not 1024 bytes). If this option is used together with the -b option, Wireshark will stop writing to the current capture file and switch to the next one if filesize is reached.
files:value
Stop writing to capture files after value number of files were written.
-b <capture ring buffer option>

If a maximum capture file size was specified, this option causes Wireshark to run in “ring buffer” mode, with the specified number of files. In “ring buffer” mode, Wireshark will write to several capture files. Their name is based on the number of the file and on the creation date and time.

When the first capture file fills up Wireshark will switch to writing to the next file, and so on. With the <command>files</command> option it’s also possible to form a “ring buffer.” This will fill up new files until the number of files specified, at which point the data in the first file will be discarded so a new file can be written.

If the optional <command>duration</command> is specified, Wireshark will also switch to the next file when the specified number of seconds has elapsed even if the current file is not completely fills up.

duration</command>:value
Switch to the next file after value seconds have elapsed, even if the current file is not completely filled up.
filesize</command>:value
Switch to the next file after it reaches a size of value kilobytes (where a kilobyte is 1000 bytes, not 1024 bytes).
files</command>:value
Begin again with the first file after value number of files were written (form a ring buffer).
-B <capture buffer size>
Set capture buffer size (in MB, default is 1MB). This is used by the capture driver to buffer packet data until that data can be written to disk. If you encounter packet drops while capturing, try to increase this size. Not supported on some platforms.
-c <capture packet count>
This option specifies the maximum number of packets to capture when capturing live data. It would be used in conjunction with the -k option.
-D

Print a list of the interfaces on which Wireshark can capture, then exit. For each network interface, a number and an interface name, possibly followed by a text description of the interface, is printed. The interface name or the number can be supplied to the -i flag to specify an interface on which to capture.

This can be useful on systems that don’t have a command to list them (e.g., Windows systems, or UNIX systems lacking ifconfig -a). The number can be especially useful on Windows, where the interface name is a GUID.

Note that “can capture” means that Wireshark was able to open that device to do a live capture. If, on your system, a program doing a network capture must be run from an account with special privileges (for example, as root), then, if Wireshark is run with the -D flag and is not run from such an account, it will not list any interfaces.

-f <capture filter>
This option sets the initial capture filter expression to be used when capturing packets.
-g <packet number>
After reading in a capture file using the -r flag, go to the given packet number.
-h
The -h option requests Wireshark to print its version and usage instructions (as shown above) and exit.
-i <capture interface>

Set the name of the network interface or pipe to use for live packet capture.

Network interface names should match one of the names listed in wireshark -D (described above). A number, as reported by wireshark -D, can also be used. If you’re using UNIX, netstat -i or ifconfig -a might also work to list interface names, although not all versions of UNIX support the -a flag to ifconfig.

If no interface is specified, Wireshark searches the list of interfaces, choosing the first non-loopback interface if there are any non-loopback interfaces, and choosing the first loopback interface if there are no non-loopback interfaces; if there are no interfaces, Wireshark reports an error and doesn’t start the capture.

Pipe names should be either the name of a FIFO (named pipe) or “-” to read data from the standard input. Data read from pipes must be in standard libpcap format.

-J <jump filter>
After reading in a capture file using the -r flag, jump to the first packet which matches the filter expression. The filter expression is in display filter format. If an exact match cannot be found the first packet afterwards is selected.
-I
Capture wireless packets in monitor mode if available.
-j
Use this option after the -J option to search backwards for a first packet to go to.
-k
The -k option specifies that Wireshark should start capturing packets immediately. This option requires the use of the -i parameter to specify the interface that packet capture will occur from.
-K <keytab file>
Use the specified file for Kerberos decryption.
-l
This option turns on automatic scrolling if the packet list pane is being updated automatically as packets arrive during a capture ( as specified by the -S flag).
-L
List the data link types supported by the interface and exit.
--list-time-stamp-types
List timestamp types configurable for the iface and exit
-m <font>
This option sets the name of the font used for most text displayed by Wireshark.
-n
Disable network object name resolution (such as hostname, TCP and UDP port names).
-N <name resolving flags>
Turns on name resolving for particular types of addresses and port numbers. The argument is a string that may contain the letters m to enable MAC address resolution, n to enable network address resolution, and t to enable transport-layer port number resolution. This overrides -n if both -N and -n are present. The letter d enables resolution from captured DNS packets. The letter v enables resolution from VLAN IDs to names.
-o <preference or recent settings>

Sets a preference or recent value, overriding the default value and any value read from a preference or recent file. The argument to the flag is a string of the form prefname:value, where prefname is the name of the preference (which is the same name that would appear in the preferences or recent file), and value is the value to which it should be set. Multiple instances of `-o <preference settings> ` can be given on a single command line.

An example of setting a single preference would be:

wireshark -o mgcp.display_dissect_tree:TRUE

An example of setting multiple preferences would be:

wireshark -o mgcp.display_dissect_tree:TRUE -o mgcp.udp.callagent_port:2627

You can get a list of all available preference strings from the preferences file. See Appendix B, Files and Folders for details.

User access tables can be overridden using “uat,” followed by the UAT file name and a valid record for the file:

wireshark -o "uat:user_dlts:\"User 0 (DLT=147)\",\"http\",\"0\",\"\",\"0\",\"\""

The example above would dissect packets with a libpcap data link type 147 as HTTP, just as if you had configured it in the DLT_USER protocol preferences.

-p
Don’t put the interface into promiscuous mode. Note that the interface might be in promiscuous mode for some other reason. Hence, -p cannot be used to ensure that the only traffic that is captured is traffic sent to or from the machine on which Wireshark is running, broadcast traffic, and multicast traffic to addresses received by that machine.
-P <path setting>

Special path settings usually detected automatically. This is used for special cases, e.g. starting Wireshark from a known location on an USB stick.

The criterion is of the form key:path, where key is one of:

persconf:path
Path of personal configuration files, like the preferences files.
persdata:path
Path of personal data files, it’s the folder initially opened. After the initialization, the recent file will keep the folder last used.
-Q
This option forces Wireshark to exit when capturing is complete. It can be used with the -c option. It must be used in conjunction with the -i and -w options.
-r <infile>
This option provides the name of a capture file for Wireshark to read and display. This capture file can be in one of the formats Wireshark understands.
-R <read (display) filter>
This option specifies a display filter to be applied when reading packets from a capture file. The syntax of this filter is that of the display filters discussed in Section 6.3, “Filtering packets while viewing”. Packets not matching the filter are discarded.
-s <capture snapshot length>
This option specifies the snapshot length to use when capturing packets. Wireshark will only capture snaplen bytes of data for each packet.
-S
This option specifies that Wireshark will display packets as it captures them. This is done by capturing in one process and displaying them in a separate process. This is the same as “Update list of packets in real time” in the “Capture Options” dialog box.
-t <time stamp format>

This option sets the format of packet timestamps that are displayed in the packet list window. The format can be one of:

r
Relative, which specifies timestamps are displayed relative to the first packet captured.
a
Absolute, which specifies that actual times be displayed for all packets.
ad
Absolute with date, which specifies that actual dates and times be displayed for all packets.
d
Delta, which specifies that timestamps are relative to the previous packet.
e
Epoch, which specifies that timestamps are seconds since epoch (Jan 1, 1970 00:00:00)
-u <s | hms>
Show timesamps as seconds (“s”, the default) or hours, minutes, and seconds (“hms”)
-v
The -v option requests Wireshark to print out its version information and exit.
-w <savefile>
This option sets the name of the file to be used to save captured packets.
-y <capture link type>
If a capture is started from the command line with -k, set the data link type to use while capturing packets. The values reported by -L are the values that can be used.
--time-stamp-type <type>
If a capture is started from the command line with -k, set the data link type to use while capturing packets. The values reported by --list-time-stamp-types are the values that can be used.
-X <eXtension option>

Specify an option to be passed to a TShark module. The eXtension option is in the form extension_key:value, where extension_key can be:

lua_script:lua_script_filename
Tells Wireshark to load the given script in addition to the default Lua scripts.
lua_script[num]:argument
Tells Wireshark to pass the given argument to the lua script identified by num, which is the number indexed order of the lua_script command. For example, if only one script was loaded with -X lua_script:my.lua, then -X lua_script1:foo will pass the string foo to the my.lua script. If two scripts were loaded, such as -X lua_script:my.lua and -X lua_script:other.lua in that order, then a -X lua_script2:bar would pass the string bar to the second lua script, namely other.lua.
-z <statistics-string>
Get Wireshark to collect various types of statistics and display the result in a window that updates in semi-real time.

11.3. Packet colorization

A very useful mechanism available in Wireshark is packet colorization. You can set up Wireshark so that it will colorize packets according to a display filter. This allows you to emphasize the packets you might be interested in.

You can find a lot of coloring rule examples at the Wireshark Wiki Coloring Rules page at https://wiki.wireshark.org/ColoringRules.

There are two types of coloring rules in Wireshark: temporary rules that are only in effect until you quit the program, and permanent rules that are saved in a preference file so that they are available the next time you run Wireshark.

Temporary rules can be added by selecting a packet and pressing the Ctrl key together with one of the number keys. This will create a coloring rule based on the currently selected conversation. It will try to create a conversation filter based on TCP first, then UDP, then IP and at last Ethernet. Temporary filters can also be created by selecting the Colorize with FilterColor X menu items when right-clicking in the packet detail pane.

To permanently colorize packets, select ViewColoring Rules…​. Wireshark will display the “Coloring Rules” dialog box as shown in Figure 11.1, “The “Coloring Rules” dialog box”.

Figure 11.1. The “Coloring Rules” dialog box

ws coloring rules dialog

If this is the first time using the Coloring Rules dialog and you’re using the default configuration profile you should see the default rules, shown above.

[Note] The first match wins

More specific rules should usually be listed before more general rules. For example, if you have a coloring rule for UDP before the one for DNS, the rule for DNS may not be applied (DNS is typically carried over UDP and the UDP rule will match first).

You can create a new rule by clicking on the + button. You can delete one or more rules by clicking the - button. The “copy” button will duplicate a rule.

You can edit a rule by double-clicking on its name or filter. In Figure 11.1, “The “Coloring Rules” dialog box” the name of the rule “Checksum Errors” is being edited. Clicking on the Foreground and Background buttons will open a color chooser (Figure 11.2, “A color chooser”) for the foreground (text) and background colors respectively.

Figure 11.2. A color chooser

ws choose color rule

The color chooser appearance depends on your operating system. The macOS color picker is shown. Select the color you desire for the selected packets and click OK.

Figure 11.3, “Using color filters with Wireshark” shows an example of several color filters being used in Wireshark. Note that the frame detail shows that the “Bad TCP” rule rule was applied, along with the matching filter.

Figure 11.3. Using color filters with Wireshark

ws coloring fields

11.4. Control Protocol dissection

The user can control how protocols are dissected.

Each protocol has its own dissector, so dissecting a complete packet will typically involve several dissectors. As Wireshark tries to find the right dissector for each packet (using static “routes” and heuristics “guessing”), it might choose the wrong dissector in your specific case. For example, Wireshark won’t know if you use a common protocol on an uncommon TCP port, e.g. using HTTP on TCP port 800 instead of the standard port 80.

There are two ways to control the relations between protocol dissectors: disable a protocol dissector completely or temporarily divert the way Wireshark calls the dissectors.

11.4.1. The “Enabled Protocols” dialog box

The Enabled Protocols dialog box lets you enable or disable specific protocols. All protocols are enabled by default. When a protocol is disabled, Wireshark stops processing a packet whenever that protocol is encountered.

[Note] Note

Disabling a protocol will prevent information about higher-layer protocols from being displayed. For example, suppose you disabled the IP protocol and selected a packet containing Ethernet, IP, TCP, and HTTP information. The Ethernet information would be displayed, but the IP, TCP and HTTP information would not - disabling IP would prevent it and the other protocols from being displayed.

To enable or disable protocols select AnalyzeEnabled Protocols…​. Wireshark will pop up the “Enabled Protocols” dialog box as shown in Figure 11.4, “The “Enabled Protocols” dialog box”.

Figure 11.4. The “Enabled Protocols” dialog box

ws enabled protocols

To disable or enable a protocol, simply click on it using the mouse or press the space bar when the protocol is highlighted. Note that typing the first few letters of the protocol name when the Enabled Protocols dialog box is active will temporarily open a search text box and automatically select the first matching protocol name (if it exists).

You must use the Save button to save your settings. The OK or Apply buttons will not save your changes permanently and they will be lost when Wireshark is closed.

You can choose from the following actions:

  1. Enable All: Enable all protocols in the list.
  2. Disable All: Disable all protocols in the list.
  3. Invert: Toggle the state of all protocols in the list.
  4. OK: Apply the changes and close the dialog box.
  5. Apply: Apply the changes and keep the dialog box open.
  6. Save: Save the settings to the disabled_protos, see Appendix B, Files and Folders for details.
  7. Cancel: Cancel the changes and close the dialog box.

11.4.2. User Specified Decodes

The “Decode As” functionality lets you temporarily divert specific protocol dissections. This might be useful for example, if you do some uncommon experiments on your network.

Decode As is accessed by selecting the AnalyzeDecode As…​. Wireshark will pop up the “Decode As” dialog box as shown in Figure 11.5, “The “Decode As” dialog box”.

Figure 11.5. The “Decode As” dialog box

ws decode as

The content of this dialog box depends on the selected packet when it was opened.

These settings will be lost if you quit Wireshark or change profile unless you save the entries in the Show User Specified Decodes…​ windows (Section 11.4.3, “Show User Specified Decodes”).

  1. Decode: Decode packets the selected way.
  2. Do not decode: Do not decode packets the selected way.
  3. Link/Network/Transport: Specify the network layer at which “Decode As” should take place. Which of these pages are available depends on the content of the selected packet when this dialog box is opened.
  4. Show Current: Open a dialog box showing the current list of user specified decodes.
  5. OK: Apply the currently selected decode and close the dialog box.
  6. Apply: Apply the currently selected decode and keep the dialog box open.
  7. Cancel: Cancel the changes and close the dialog box.

11.4.3. Show User Specified Decodes

This dialog box shows the currently active user specified decodes. These entries can be saved into current profile for later session.

Figure 11.6. The “Decode As: Show” dialog box

ws decode as show

  1. OK: Close this dialog box.
  2. Save: Save the entries in the table into current profile.
  3. Clear: Removes all user specified decodes without updating the profile.

11.5. Preferences

There are a number of preferences you can set. Simply select the EditPreferences…​ (WiresharkPreferences…​ on macOS) and Wireshark will pop up the Preferences dialog box as shown in Figure 11.7, “The preferences dialog box”, with the “User Interface” page as default. On the left side is a tree where you can select the page to be shown.

  • The OK button will apply the preferences settings and close the dialog.
  • The Apply button will apply the preferences settings and keep the dialog open.
  • The Cancel button will restore all preferences settings to the last saved state.

Figure 11.7. The preferences dialog box

ws gui preferences

11.5.1. Interface Options

In the “Capture” preferences it is possible to configure several options for the interfaces available on your computer. Select the “Capture” pane and press the Edit button. In this window it is possible to change the default link-layer header type for the interface, add a comment or choose to hide a interface from other parts of the program.

Figure 11.8. The interface options dialog box

ws gui interface options

Each row contains options for each interface available on your computer.

  • Device: the device name provided by the operating system.
  • Description: provided by the operating system.
  • Default link-layer: each interface may provide several link-layer header types. The default link-layer chosen here is the one used when you first start Wireshark. It is also possible to change this value in Section 4.5, “The “Capture Options” dialog box” when you start a capture. For a detailed description, see Section 4.12, “Link-layer header type”.
  • Comment: a user provided description of the interface. This comment will be used as a description instead of the operating system description.
  • Hide?: enable this option to hide the interface from other parts of the program.

11.6. Configuration Profiles

Configuration Profiles can be used to configure and use more than one set of preferences and configurations. Select the EditConfiguration Profiles…​ menu item or press Shift+Ctrl+A or Shift++A (macOS) and Wireshark will pop up the Configuration Profiles dialog box as shown in Figure 11.9, “The configuration profiles dialog box”. It is also possible to click in the “Profile” part of the statusbar to popup a menu with available Configuration Profiles (Figure 3.21, “The Statusbar with a configuration profile menu”).

Configuration files stored in each profile include:

All other configurations are stored in the personal configuration folder and are common to all profiles.

Figure 11.9. The configuration profiles dialog box

ws gui config profiles

New (+)
Create a new profile. The name of the created profile is “New profile” and is highlighted so that you can more easily change it.
Delete (-)
Deletes the selected profile. This includes all configuration files used in this profile. It is not possible to delete the “Default” profile or global profiles.
Copy
Copies the selected profile. This copies the configuration of the profile currently selected in the list. The name of the created profile is the same as the copied profile, with the text “(copy)” and is highlighted so that you can more easily change it.
OK
This button saves all changes, applies the selected profile and closes the dialog.
Cancel
Close this dialog. This will discard unsaved settings, new profiles will not be added and deleted profiles will not be deleted.
Help
Show this help page.

11.7. User Table

The User Table editor is used for managing various tables in wireshark. Its main dialog works very similarly to that of Section 11.3, “Packet colorization”.

11.8. Display Filter Macros

Display Filter Macros are a mechanism to create shortcuts for complex filters. For example defining a display filter macro named tcp_conv whose text is ( (ip.src == $1 and ip.dst == $2 and tcp.srcport == $3 and tcp.dstport == $4) or (ip.src == $2 and ip.dst == $1 and tcp.srcport == $4 and tcp.dstport == $3) ) would allow to use a display filter like ${tcp_conv:10.1.1.2;10.1.1.3;1200;1400} instead of typing the whole filter.

Display Filter Macros can be managed with a user table, as described in Section 11.7, “User Table”, by selecting AnalyzeDisplay Filter Macros from the menu. The User Table has the following fields:

Name
The name of the macro.
Text
The replacement text for the macro it uses $1, $2, $3, …​ as the input arguments.

11.9. ESS Category Attributes

Wireshark uses this table to map ESS Security Category attributes to textual representations. The values to put in this table are usually found in a XML SPIF, which is used for defining security labels.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

Tag Set
An Object Identifier representing the Category Tag Set.
Value
The value (Label And Cert Value) representing the Category.
Name
The textual representation for the value.

11.10. MaxMind Database Paths

If your copy of Wireshark supports MaxMind’s MaxMindDB library, you can use their databases to match IP addresses to countries, cites, autonomous system numbers, and other bits of information. Some databases are available at no cost, while others require a licensing fee. See the MaxMind web site for more information.

The configuration for the MaxMind database is a user table, as described in Section 11.7, “User Table”, with the following fields:

Database pathname
This specifies a directory containing MaxMind data files. Any files ending with .mmdb will be automatically loaded.

The locations for your data files are up to you, but /usr/share/GeoIP and /var/lib/GeoIP are common on Linux and C:\ProgramData\GeoIP, C:\Program Files\Wireshark\GeoIP might be good choices on Windows.

Previous versions of Wireshark supported MaxMind’s original GeoIP Legacy database format. They were configured similar to MaxMindDB files above, except GeoIP files must begin with Geo and end with .dat. They are no longer supported and MaxMind stopped distributing GeoLite Legacy databases in April 2018.

11.11. IKEv2 decryption table

Wireshark can decrypt Encrypted Payloads of IKEv2 (Internet Key Exchange version 2) packets if necessary information is provided. Note that you can decrypt only IKEv2 packets with this feature. If you want to decrypt IKEv1 packets or ESP packets, use Log Filename setting under ISAKMP protocol preference or settings under ESP protocol preference respectively.

This is handled by a user table, as described in Section 11.7, “User Table”, with the following fields:

Initiator’s SPI
Initiator’s SPI of the IKE_SA. This field takes hexadecimal string without “0x” prefix and the length must be 16 hex chars (represents 8 octets).
Responder’s SPI
Responder’s SPI of the IKE_SA. This field takes hexadecimal string without “0x” prefix and the length must be 16 hex chars (represents 8 octets).
SK_ei
Key used to encrypt/decrypt IKEv2 packets from initiator to responder. This field takes hexadecimal string without “0x” prefix and its length must meet the requirement of the encryption algorithm selected.
SK_er
Key used to encrypt/decrypt IKEv2 packets from responder to initiator. This field takes hexadecimal string without “0x” prefix and its length must meet the requirement of the encryption algorithm selected.
Encryption Algorithm
Encryption algorithm of the IKE_SA.
SK_ai
Key used to calculate Integrity Checksum Data for IKEv2 packets from responder to initiator. This field takes hexadecimal string without “0x” prefix and its length must meet the requirement of the integrity algorithm selected.
SK_ar
Key used to calculate Integrity Checksum Data for IKEv2 packets from initiator to responder. This field takes hexadecimal string without “0x” prefix and its length must meet the requirement of the integrity algorithm selected.
Integrity Algorithm
Integrity algorithm of the IKE_SA.

11.12. Object Identifiers

Many protocols that use ASN.1 use Object Identifiers (OIDs) to uniquely identify certain pieces of information. In many cases, they are used in an extension mechanism so that new object identifiers (and associated values) may be defined without needing to change the base standard.

Whilst Wireshark has knowledge about many of the OIDs and the syntax of their associated values, the extensibility means that other values may be encountered.

Wireshark uses this table to allow the user to define the name and syntax of Object Identifiers that Wireshark does not know about (for example, a privately defined X.400 extension). It also allows the user to override the name and syntax of Object Identifiers that Wireshark does know about (e.g. changing the name “id-at-countryName” to just “c”).

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

OID
The string representation of the Object Identifier e.g. “2.5.4.6”.
Name
The name that should be displayed by Wireshark when the Object Identifier is dissected e.g. (“c”);
Syntax
The syntax of the value associated with the Object Identifier. This must be one of the syntaxes that Wireshark already knows about (e.g. “PrintableString”).

11.13. PRES Users Context List

Wireshark uses this table to map a presentation context identifier to a given object identifier when the capture does not contain a PRES package with a presentation context definition list for the conversation.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

Context Id
An Integer representing the presentation context identifier for which this association is valid.
Syntax Name OID
The object identifier representing the abstract syntax name, which defines the protocol that is carried over this association.

11.14. SCCP users Table

Wireshark uses this table to map specific protocols to a certain DPC/SSN combination for SCCP.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

Network Indicator
An Integer representing the network indicator for which this association is valid.
Called DPCs
An range of integers representing the dpcs for which this association is valid.
Called SSNs
An range of integers representing the ssns for which this association is valid.
User protocol
The protocol that is carried over this association

11.15. SMI (MIB and PIB) Modules

If your copy of Wireshark supports libSMI, you can specify a list of MIB and PIB modules here. The COPS and SNMP dissectors can use them to resolve OIDs.

Module name
The name of the module, e.g. IF-MIB.

11.16. SMI (MIB and PIB) Paths

If your copy of Wireshark supports libSMI, you can specify one or more paths to MIB and PIB modules here.

Directory name
A module directory, e.g. /usr/local/snmp/mibs. Wireshark automatically uses the standard SMI path for your system, so you usually don’t have to add anything here.

11.17. SNMP Enterprise Specific Trap Types

Wireshark uses this table to map specific-trap values to user defined descriptions in a Trap PDU. The description is shown in the packet details specific-trap element.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

Enterprise OID
The object identifier representing the object generating the trap.
Trap Id
An Integer representing the specific-trap code.
Description
The description to show in the packet details.

11.18. SNMP users Table

Wireshark uses this table to verify authentication and to decrypt encrypted SNMPv3 packets.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

Engine ID
If given this entry will be used only for packets whose engine id is this. This field takes an hexadecimal string in the form 0102030405.
Username
This is the userName. When a single user has more than one password for different SNMP-engines the first entry to match both is taken, if you need a catch all engine-id (empty) that entry should be the last one.
Authentication model
Which auth model to use (either “MD5” or “SHA1”).
Password
The authentication password. Use \xDD for unprintable characters. An hexadecimal password must be entered as a sequence of \xDD characters. For example the hex password 010203040506 must be entered as \x01\x02\x03\x04\x05\x06. The \ character must be treated as an unprintable character, i.e. it must be entered as \x5C or \x5c.
Privacy protocol
Which encryption algorithm to use (either “DES” or “AES”).
Privacy password
The privacy password. Use \xDD for unprintable characters. An hexadecimal password must be entered as a sequence of \xDD characters. For example the hex password 010203040506 must be entered as \x01\x02\x03\x04\x05\x06. The \ character must be treated as an unprintable character, i.e. it must be entered as \x5C or \x5c.

11.19. Tektronix K12xx/15 RF5 protocols Table

The Tektronix K12xx/15 rf5 file format uses helper files (*.stk) to identify the various protocols that are used by a certain interface. Wireshark doesn’t read these stk files, it uses a table that helps it identify which lowest layer protocol to use.

Stk file to protocol matching is handled by a user table, as described in Section 11.7, “User Table”, with the following fields:

Match string
A partial match for an stk filename, the first match wins, so if you have a specific case and a general one the specific one must appear first in the list.
Protocol
This is the name of the encapsulating protocol (the lowest layer in the packet data) it can be either just the name of the protocol (e.g. mtp2, eth_witoutfcs, sscf-nni ) or the name of the encapsulation protocol and the “application” protocol over it separated by a colon (e.g sscop:sscf-nni, sscop:alcap, sscop:nbap, …​)

11.20. User DLTs protocol table

When a pcap file uses one of the user DLTs (147 to 162) wireshark uses this table to know which protocol(s) to use for each user DLT.

This table is a user table, as described in Section 11.7, “User Table”, with the following fields:

DLT
One of the user dlts.
Payload protocol
This is the name of the payload protocol (the lowest layer in the packet data). (e.g. “eth” for ethernet, “ip” for IPv4)
Header size
If there is a header protocol (before the payload protocol) this tells which size this header is. A value of 0 disables the header protocol.
Header protocol
The name of the header protocol to be used (uses “data” as default).
Trailer size
If there is a trailer protocol (after the payload protocol) this tells which size this trailer is. A value of 0 disables the trailer protocol.
Trailer protocol
The name of the trailer protocol to be used (uses “data” as default).

Chapter 12. MATE

12.1. Introduction

MATE: Meta Analysis and Tracing Engine

What is MATE? Well, to keep it very short, with MATE you can create user configurable extension(s) of the display filter engine.

MATE’s goal is to enable users to filter frames based on information extracted from related frames or information on how frames relate to each other. MATE was written to help troubleshooting gateways and other systems where a "use" involves more protocols. However MATE can be used as well to analyze other issues regarding a interaction between packets like response times, incompleteness of transactions, presence/absence of certain attributes in a group of PDUs and more.

MATE is a Wireshark plugin that allows the user to specify how different frames are related to each other. To do so, MATE extracts data from the frames' tree and then, using that information, tries to group the frames based on how MATE is configured. Once the PDUs are related MATE will create a "protocol" tree with fields the user can filter with. The fields will be almost the same for all the related frames, so one can filter a complete session spanning several frames containing more protocols based on an attribute appearing in some related frame. Other than that MATE allows to filter frames based on response times, number of PDUs in a group and a lot more.

So far MATE has been used to:

  • Filter all packets of a call using various protocols knowing just the calling number. (MATE’s original goal)
  • Filter all packets of all calls using various protocols based on the release cause of one of its "segments".
  • Extrapolate slow transactions from very "dense" captures. (finding requests that timeout)
  • Find incomplete transactions (no responses)
  • Follow requests through more gateways/proxies.
  • more…​

12.2. Getting Started

These are the steps to try out MATE:

  • Run Wireshark and check if the plugin is installed correct (MATE should appear in Help→About→Plugins)
  • Get a configuration file e.g. tcp.mate (see Mate/Examples for more) and place it somewhere on your harddisk.
  • Go to Preferences→Protocols→MATE and set the config filename to the file you want to use (you don’t have to restart Wireshark)
  • Load a corresponding capture file (e.g. http.cap) and see if MATE has added some new display filter fields, something like: mate tcp_pdu:1->tcp_ses:1 or, at prompt: path_to/wireshark -o "mate.config: tcp.mate" -r http.cap.

If anything went well, your packet details might look something like this:

ws mate tcp output

12.3. MATE Manual

12.3.1. Introduction

MATE creates a filterable tree based on information contained in frames that share some relationship with information obtained from other frames. The way this relationships are made is described in a configuration file. The configuration file tells MATE what makes a PDU and how to relate it to other PDUs.

MATE analyzes each frame to extract relevant information from the "protocol" tree of that frame. The extracted information is contained in MATE PDUs; these contain a list of relevant attributes taken from the tree. From now on, I will use the term "PDU" to refer to the objects created by MATE containing the relevant information extracted from the frame; I’ll use "frame" to refer to the "raw" information extracted by the various dissectors that pre-analyzed the frame.

For every PDU, MATE checks if it belongs to an existing "Group of PDUs" (Gop). If it does, it assigns the PDU to that Gop and moves any new relevant atributes to the Gop’s attribute list. How and when do PDUs belong to Gops is described in the configuration file as well.

Every time a Gop is assigned a new PDU, MATE will check if it matches the conditions to make it belong to a "Group of Groups" (Gog). Naturally the conditions that make a Gop belong to a Gog are taken from the configuration file as well.

Once MATE is done analyzing the frame it will be able to create a "protocol" tree for each frame based on the PDUs, the Gops they belong to and naturally any Gogs the former belongs to.

How to tell MATE what to extract, how to group it and then how to relate those groups is made using AVPs and AVPLs.

Information in MATE is contained in Attribute/Value Pairs (AVPs). AVPs are made of two strings: the name and the value. AVPs are used in the configuration and there they have an operator as well. There are various ways AVPs can be matched against each other using those operators.

AVPs are grouped into AVP Lists (AVPLs). PDUs, Gops and Gogs have an AVPL each. Their AVPLs will be matched in various ways against others coming from the configuration file.

MATE will be instructed how to extract AVPs from frames in order to create a PDU with an AVPL. It will be instructed as well, how to match that AVPL against the AVPLs of other similar PDUs in order to relate them. In MATE the relationship between PDUs is a Gop, it has an AVPL as well. MATE will be configured with other AVPLs to operate against the Gop’s AVPL to relate Gops together into Gogs.

A good understanding on how AVPs and AVPLs work is fundamental to understand how MATE works.

12.3.2. Attribute Value Pairs

Information used by MATE to relate different frames is contained in Attribute/ Value Pairs (AVPs). AVPs are made of two strings - the name and the value. When AVPs are used in the configuration, an operator is defined as well. There are various ways AVPs can be matched against each other using those operators.

  avp_name="avp's value"
  another_name= "1234 is the value"

The name is a string used to refer to a "kind" of an AVP. Two AVPs won’t match unless their names are identical.

You should not use uppercase characters in names, or names that start with . or _. Capitalized names are reserved for configuration parameters (we’ll call them keywords); nothing forbids you from using capitalized strings for other things as well but it probably would be confusing. I’ll avoid using capitalized words for anything but the keywords in this document, the reference manual, the examples and the base library. Names that start with a . would be very confusing as well because in the old grammar, AVPL transformations use names starting with a . to indicate they belong to the replacement AVPL.

The value is a string that is either set in the configuration (for configuration AVPs) or by wireshark while extracting interesting fields from a frame’s tree. The values extracted from fields use the same representation as they do in filter strings except that no quotes are used.

The name can contain only alphanumeric characters, "_", and ".". The name ends with an operator.

The value will be dealt with as a string even if it is a number. If there are any spaces in the value, the value must be between quotes "".

   ip_addr=10.10.10.11,
   tcp_port=1234,
   binary_data=01:23:45:67:89:ab:cd:ef,
   parameter12=0x23aa,
   parameter_with_spaces="this value has spaces"

The way two AVPs with the same name might match is described by the operator. Remember two AVPs won’t match unless their names are identical. In MATE, match operations are always made between the AVPs extracted from frames (called data AVPs) and the configuration’s AVPs.

Currently defined MATE’s AVP match operators are:

  • Equal = will match if the string given completely matches the data AVP’s value string
  • Not Equal ! will match only if the given value string is not equal to the data AVP’s value string
  • One Of {} will match if one of the possible strings listed is equal to the data AVP’s value string
  • Starts With ^ will match if the string given matches the first characters of the data AVP’s value string
  • Ends With $ will match if the string given matches the last characters of the data AVP’s value string
  • Contains ~ will match if the string given matches any substring of the data AVP’s value string
  • Lower Than < will match if the data AVP’s value string is semantically lower than the string given
  • Higher Than > will match if the data AVP’s value string is semantically higher than the string given
  • Exists ? (the ? can be ommited) will match as far as a data AVP of the given name exists

12.3.3. AVP lists

An AVPL is a set of diverse AVPs that can be matched against other AVPLs. Every PDU, Gop and Gog has an AVPL that contains the information regarding it. The rules that MATE uses to group Pdus and Gops are AVPL operations.

There will never be two identical AVPs in a given AVPL. However, we can have more than one AVP with the same name in an AVPL as long as their values are different.

Some AVPL examples:

  ( addr=10.20.30.40, addr=192.168.0.1, tcp_port=21, tcp_port=32534, user_cmd=PORT, data_port=12344, data_addr=192.168.0.1 )
  ( addr=10.20.30.40, addr=192.168.0.1, channel_id=22:23, message_type=Setup, calling_number=1244556673 )
  ( addr=10.20.30.40, addr=192.168.0.1, ses_id=01:23:45:67:89:ab:cd:ef )
  ( user_id=pippo, calling_number=1244556673, assigned_ip=10.23.22.123 )

In MATE there are two types of AVPLs:

  • data AVPLs that contain information extracted from frames.
  • operation AVPLs that come from the configuration and are used to tell MATE how to relate items based on their data AVPLs.

Data AVPLs can be operated against operation AVPLs in various ways:

  • Loose Match: Will match if at least one of the AVPs of each AVPL match. If it matches it will return an AVPL containing all AVPs from the operand AVPL that did match the operator’s AVPs.
  • "Every" Match: Will match if none of the AVPs of the operator AVPL fails to match a present AVP in the operand AVPL, even if not all of the operator’s AVPs have a match. If it matches it will return an AVPL containing all AVPs from the operand AVPL that did match one AVP in the operator AVPL.
  • Strict Match: Will match if and only if every one of the operator’s AVPs have at least one match in the operand AVPL. If it matches it will return an AVPL containing the AVPs from the operand that matched.
  • There’s also a Merge operation that is to be performed between AVPLs where all the AVPs that don’t exist in the operand AVPL but exist in the operand will be added to the operand AVPL.
  • Other than that there are Transformations - a combination of a match AVPL and an AVPL to merge.

12.3.4. MATE Analysis

MATE’s analysis of a frame is performed in three phases:

  • In the first phase, MATE attempts to extract a MATE Pdu from the frame’s protocol tree. MATE will create a Pdu if MATE’s config has a Pdu declaration whose Proto is contained in the frame.
  • In the second phase, if a Pdu has been extracted from the frame, MATE will try to group it to other Pdus into a Gop (Group of Pdus) by matching the key criteria given by a Gop declaration. If there is no Gop yet with the key criteria for the Pdu, MATE will try to create a new Gop for it if it matches the Start criterium given in the Gop declaration.
  • In the third phase, if there’s a Gop for the Pdu, MATE will try to group this Gop with other Gops into a Gog (Group of Groups) using the criteria given by the Member criteria of a Gog declaration.
ws mate analysis

The extraction and matching logic comes from MATE’s configuration; MATE’s configuration file is declared by the mate.config preference. By default it is an empty string which means: do not configure MATE.

The config file tells MATE what to look for in frames; How to make PDUs out of it; How will PDUs be related to other similar PDUs into Gops; And how Gops relate into Gogs.

The MATE configuration file is a list of declarations. There are 4 types of declarations: Transform, Pdu, Gop and Gog.

12.3.4.1. Mate’s PDU’s

MATE will look in the tree of every frame to see if there is useful data to extract, and if there is, it will create one or more PDU objects containing the useful information.

The first part of MATE’s analysis is the "PDU extraction"; there are various "Actions" that are used to instruct MATE what has to be extracted from the current frame’s tree into MATE’s PDUs.

12.3.4.1.1. PDU data extraction

MATE will make a Pdu for each different proto field of Proto type present in the frame. MATE will fetch from the field’s tree those fields that are defined in the Section 12.8.1, “Pdsu’s configuration actions” declaration whose initial offset in the frame is within the boundaries of the current Proto and those of the given Transport and Payload statements.

Pdu dns_pdu Proto dns Transport ip {
    Extract addr From ip.addr;
    Extract dns_id From dns.id;
    Extract dns_resp From dns.flags.response;
};

MATE will make a Pdu for each different proto field of Proto type present in the frame. MATE will fetch from the field’s tree those fields that are defined in the Section 12.8.1, “Pdsu’s configuration actions” AVPL whose initial offset in the frame is within the boundaries of the current Proto and those of the various assigned Transports.

ws mate dns pane

Once MATE has found a Proto field for which to create a Pdu from the frame it will move backwards in the frame looking for the respective Transport fields. After that it will create AVPs named as each of those given in the rest of the AVPL for every instance of the fields declared as its values.

ws mate dns pdu

Sometimes we need information from more than one Transport protocol. In that case MATE will check the frame looking backwards to look for the various Transport protocols in the given stack. MATE will choose only the closest transport boundary per "protocol" in the frame.

This way we’ll have all Pdus for every Proto that appears in a frame match its relative transports.

Pdu isup_pdu Proto isup Transport mtp3/ip {
        Extract m3pc From mtp3.dpc;
        Extract m3pc From mtp3.opc;
        Extract cic From isup.cic;
        Extract addr From ip.addr;
        Extract isup_msg From isup.message_type;
};
ws mate isup over mtp3 over ip

This allows to assign the right Transport to the Pdu avoiding duplicate transport protocol entries (in case of tunneled ip over ip for example).

Pdu ftp_pdu Proto ftp Transport tcp/ip {
        Extract addr From ip.addr;
        Extract port From tcp.port;
        Extract ftp_cmd From ftp.command;
};
ws mate ftp over gre

Other than the mandatory Transport there is also an optional Payload statement, which works pretty much as Transport but refers to elements after the Proto's range. It is useful in those cases where the payload protocol might not appear in a Pdu but nevertheless the Pdu belongs to the same category.

Pdu mmse_over_http_pdu Proto http Transport tcp/ip {

        Payload mmse;

        Extract addr From ip.addr;
        Extract port From tcp.port;
        Extract method From http.request.method;
        Extract content From http.content_type;
        Extract http_rq From http.request;
        Extract resp From http.response.code;
        Extract host From http.host;
        Extract trx From mmse.transaction_id;
        Extract msg_type From mmse.message_type;
        Extract notify_status From mmse.status;
        Extract send_status From mmse.response_status;
};
ws mate mmse over http
12.3.4.1.2. Conditions on which to create PDUs

There might be cases in which we won’t want MATE to create a PDU unless some of its extracted attributes meet or do not meet some criteria. For that we use the Criteria statements of the Pdu declarations.

Pdu isup_pdu Proto isup Transport mtp3/ip {
    ...

   // MATE will create isup_pdu PDUs only when there is not a point code '1234'
   Criteria Reject Strict (m3pc=1234);
};

Pdu ftp_pdu Proto ftp Transport tcp/ip {
    ...

    // MATE will create ftp_pdu PDUs only when they go to port 21 of our ftp_server
    Criteria Accept Strict (addr=10.10.10.10, port=21);
};

The Criteria statement is given an action (Accept or Reject), a match mode (Strict, Loose or Every) and an AVPL against which to match the currently extracted one.

12.3.4.1.3. Transforming the attributes of a PDU

Once the fields have been extracted into the Pdu’s AVPL, MATE will apply any declared transformation to it. The way transforms are applied and how they work is described later on. However it’s useful to know that once the AVPL for the Pdu is created, it may be transformed before being analyzed. That way we can massage the data to simplify the analysis.

12.3.4.1.4. MATE’s PDU tree

Every successfully created Pdu will add a MATE tree to the frame dissection. If the Pdu is not related to any Gop, the tree for the Pdu will contain just the Pdu’s info, if it is assigned to a Gop, the tree will also contain the Gop items, and the same applies for the Gog level.

mate dns_pdu:1
    dns_pdu: 1
        dns_pdu time: 3.750000
        dns_pdu Attributes
            dns_resp: 0
            dns_id: 36012
            addr: 10.194.4.11
            addr: 10.194.24.35

The Pdu’s tree contains some filterable fields

  • mate.dns_pdu will contain the number of the "dns_pdu" Pdu
  • mate.dns_pdu.RelativeTime will contain the time passed since the beginning of the capture in seconds
  • the tree will contain the various attributes of the Pdu as well, these will all be strings (to be used in filters as "10.0.0.1", not as 10.0.0.1)

    • mate.dns_pdu.dns_resp
    • mate.dns_pdu.dns_id
    • mate.dns_pdu.addr

12.3.4.2. Grouping Pdus together (Gop)

Once MATE has created the Pdus it passes to the Pdu analysis phase. During the PDU analysis phase MATE will try to group Pdus of the same type into Groups of Pdus (aka *Gop*s) and copy some AVPs from the Pdu’s AVPL to the Gop’s AVPL.

ws mate pdu analysis
12.3.4.2.1. What can belong to a Gop

Given a Pdu, the first thing MATE will do is to check if there is any Gop declaration in the configuration for the given Pdu type. If so, it will use its Match AVPL to match it against the Pdu’s AVPL; if they don’t match, the analysis phase is done. If there is a match, the AVPL is the Gop’s candidate key which will be used to search the Gop’s index for the Gop to which to assign the current PDU. If there is no such Gop and this Pdu does not match the Start criteria of a Gop declaration for the Pdu type, the Pdu will remain unassigned and only the analysis phase will be done.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port);
Gop dns_req On dns_pdu Match (addr, addr, dns_id);
Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic);
12.3.4.2.2. Start of a Gop

If there was a match, the candidate key will be used to search the Gop’s index to see if there is already a Gop matching the Gop’s key the same way. If there is such a match in the Gops collection, and the PDU doesn’t match the Start AVPL for its kind, the PDU will be assigned to the matching Gop. If it is a Start match, MATE will check whether or not that Gop has been already stopped. If the Gop has been stopped, a new Gop will be created and will replace the old one in the Gop’s index.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
    Start (ftp_cmd=USER);
};

Gop dns_req On dns_pdu Match (addr, addr, dns_id) {
    Start (dns_resp=0);
};

Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
    Start (isup_msg=1);
};

If no Start is given for a Gop, a Pdu whose AVPL matches an existing Gog’s key will act as the start of a Gop.

12.3.4.2.3. What goes into the Gop’s AVPL

Once we know a Gop exists and the Pdu has been assigned to it, MATE will copy into the Gop’s AVPL all the attributes matching the key plus any AVPs of the Pdu’s AVPL matching the Extra AVPL.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
    Start (ftp_cmd=USER);
    Extra (pasv_prt, pasv_addr);
};

Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
    Start (isup_msg=1);
    Extra (calling, called);
};
12.3.4.2.4. End of a Gop

Once the Pdu has been assigned to the Gop, MATE will check whether or not the Pdu matches the Stop, if it happens, MATE will mark the Gop as stopped. Even after stopped, a Gop may get assigned new Pdus matching its key, unless such Pdu matches Start. If it does, MATE will instead create a new Gop starting with that Pdu.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
    Start (ftp_cmd=USER);
    Stop (ftp_cmd=QUIT); // The response to the QUIT command will be assigned to the same Gop
    Extra (pasv_prt, pasv_addr);
};

Gop dns_req On dns_pdu Match (addr, addr, dns_id) {
    Start (dns_resp=0);
    Stop (dns_resp=1);
};

Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
    Start (isup_msg=1); // IAM
    Stop (isup_msg=16); // RLC
    Extra (calling, called);
};

If no Stop criterium is stated for a given Gop, the Gop will be stopped as soon as it is created. However, as with any other Gop, Pdus matching the Gop’s key will still be assigned to the Gop unless they match a Start condition, in which case a new Gop using the same key will be created.

12.3.4.3. Gop’s tree

For every frame containing a Pdu that belongs to a Gop, MATE will create a tree for that Gop.

The example below represents the tree created by the dns_pdu and dns_req examples.

...
mate dns_pdu:6->dns_req:1
    dns_pdu: 6
        dns_pdu time: 2.103063
        dns_pdu time since begining of Gop: 2.103063
        dns_req: 1
            dns_req Attributes
                dns_id: 36012
                addr: 10.194.4.11
                addr: 10.194.24.35
            dns_req Times
                dns_req start time: 0.000000
                dns_req hold time: 2.103063
                dns_req duration: 2.103063
            dns_req number of PDUs: 2
                Start PDU: in frame 1
                Stop PDU: in frame 6 (2.103063 : 2.103063)
        dns_pdu Attributes
            dns_resp: 1
            dns_id: 36012
            addr: 10.194.4.11
            addr: 10.194.24.35

Other than the pdu’s tree, this one contains information regarding the relationship between the Pdus that belong to the Gop. That way we have:

  • mate.dns_req which contains the id of this dns_req Gop. This will be present in frames that belong to dns_req Gops.
  • mate.dns_req.dns_id and mate.dns_req.addr which represent the values of the attributes copied into the Gop.
  • the timers of the Gop

    • mate.dns_req.StartTime time (in seconds) passed since beginning of capture until Gop’s start.
    • mate.dns_req.Time time passed between the start Pdu and the stop Pdu assigned to this Gop (only created if a Stop criterion has been declared for the Gop and a matching Pdu has arrived).
    • mate.dns_req.Duration time passed between the start Pdu and the last Pdu assigned to this Gop.
  • mate.dns_req.NumOfPdus the number of Pdus that belong to this Gop

    • a filterable list of frame numbers of the pdus of this Gop
12.3.4.3.1. Gop’s timers

Note that there are two "timers" for a Gop:

  • Time, which is defined only for Gops that have been Stopped, and gives the time passed between the Start and the Stop Pdus.
  • Duration, which is defined for every Gop regardles of its state, and give the time passed between its Start Pdu and the last Pdu that was assigned to that Gop.

So:

  • we can filter for Pdus that belong to Gops that have been Stopped with mate.xxx.Time
  • we can filter for Pdus that belong to unstopped Gops with mate.xxx && mate.xxx.Time
  • we can filter for Pdus that belong to stopped Gops using mate.xxx.Duration
  • we can filter for Pdus that belong to Gops that have taken more (or less) time that 0.5s to complete with mate.xxx.Time > 0.5 (you can try these also as color filters to find out when response times start to grow)

12.3.4.4. Grouping Gops together (Gog)

When Gops are created, or whenever their AVPL changes, Gops are (re)analyzed to check if they match an existent group of groups (Gog) or can create a new one. The Gop analysis is divided into two phases. In the first phase, the still unassigned Gop is checked to verify whether it belongs to an already existing Gog or may create a new one. The second phase eventually checks the Gog and registers its keys in the Gogs index.

ws mate gop analysis

There are several reasons for the author to believe that this feature needs to be reimplemented, so probably there will be deep changes in the way this is done in the near future. This section of the documentation reflects the version of MATE as of wireshark 0.10.9; in future releases this will change.

12.3.4.4.1. Declaring a Group Of Groups

The first thing we have to do configuring a Gog is to tell MATE that it exists.

Gog web_use {
   ...
};
12.3.4.4.2. Telling MATE what could be a Gog member

Then we have to tell MATE what to look for a match in the candidate Gops.

Gog web_use {
    Member http_ses (host);
    Member dns_req (host);
};
12.3.4.4.3. Getting interesting data into the Gop

Most often, also other attributes than those used for matching would be interesting. In order to copy from Gop to Gog other interesting attributes, we might use Extra like we do for Gops.

Gog web_use {
    ...
    Extra (cookie);
};
12.3.4.4.4. Gog’s tree
mate http_pdu:4->http_req:2->http_use:1
    http_pdu: 4
        http_pdu time: 1.309847
        http_pdu time since begining of Gop: 0.218930
        http_req: 2
            ... (the gop's tree for http_req: 2) ..
        http_use: 1
            http_use Attributes
                host: www.example.com
            http_use Times
                http_use start time: 0.000000
                http_use duration: 1.309847
            number of GOPs: 3
                dns_req: 1
                    ... (the gop's tree for dns_req: 1) ..
                http_req: 1
                    ... (the gop's tree for http_req: 1) ..
                http_req of current frame: 2

We can filter on:

  • mate.http_use.Duration time elapsed between the first frame of a Gog and the last one assigned to it.
  • the attributess passed to the Gog

    • mate.http_use.host

12.3.4.5. AVPL Transforms

A Transform is a sequence of Match rules optionally completed with modification of the match result by an additional AVPL. Such modification may be an Insert (merge) or a Replace. Transforms can be used as helpers to manipulate an item’s AVPL before it is processed further. They come to be very helpful in several cases.

12.3.4.5.1. Syntax

AVPL Transformations are declared in the following way:

 Transform name {
   Match [Strict|Every|Loose] match_avpl [Insert|Replace] modify_avpl ;
   ...
 };

The name is the handle to the AVPL transformation. It is used to refer to the transform when invoking it later.

The Match declarations instruct MATE what and how to match against the data AVPL and how to modify the data AVPL if the match succeeds. They will be executed in the order they appear in the config file whenever they are invoked.

The optional match mode qualifier (Strict, Every, or Loose) is used to choose the match mode as explained above; Strict is a default value which may be omitted.

The optional modification mode qualifier instructs MATE how the modify AVPL should be used:

  • the default value Insert (which may be omitted) causes the modify_avpl to be merged to the existing data AVPL,
  • the Replace causes all the matching AVPs from the data AVPL to be replaced by the modify_avpl.

The modify_avpl may be an empty one; this comes useful in some cases for both Insert and Replace modification modes.

Examples:

 Transform insert_name_and {
   Match Strict (host=10.10.10.10, port=2345) Insert (name=JohnDoe);
};

adds name=JohnDoe to the data AVPL if it contains host=10.10.10.10 and port=2345

Transform insert_name_or {
   Match Loose (host=10.10.10.10, port=2345) Insert (name=JohnDoe);
};

adds name=JohnDoe to the data AVPL if it contains host=10.10.10.10 or port=2345

Transform replace_ip_address {
   Match (host=10.10.10.10) Replace (host=192.168.10.10);
};

replaces the original host=10.10.10.10 by host=192.168.10.10

Transform add_ip_address {
   Match (host=10.10.10.10) (host=192.168.10.10);
};

adds (inserts) host=192.168.10.10 to the AVPL, keeping the original host=10.10.10.10 in it too

 Transform replace_may_be_surprising {
   Match Loose (a=aaaa, b=bbbb) Replace (c=cccc, d=dddd);
 };

gives the following results:

  • (a=aaaa, b=eeee) gets transformed to (b=eeee, c=cccc, d=dddd) because a=aaaa did match so it got replaced while b=eeee did not match so it has been left intact,
  • (a=aaaa, b=bbbb) gets transformed to (c=cccc, d=dddd) because both a=aaaa and b=bbbb did match.
12.3.4.5.2. Usage

Once declared, Transforms can be added to the declarations of PDUs, Gops or Gogs. This is done by adding the Transform name_list statement to the declaration:

Pdu my_proto_pdu Proto my_proto Transport ip {
    Extract addr From ip.addr;
    ...
    Transform my_pdu_transform[, other_pdu_transform[, yet_another_pdu_transform]];
};
  • In case of PDU, the list of transforms is applied against the PDU’s AVPL after its creation.
  • In case of Gop and Gog, the list of transforms is applied against their respective AVPLs when they are created and every time they change.

12.3.4.6. Operation

ws mate transform
  • A list of previously declared Transforms may be given to every Item (Pdu, Gop, or Gog), using the Transform statement.
  • Every time the AVPL of an item changes, it will be operated against all the Transforms on the list given to that item. The Transforms on the list are applied left to right.
  • Inside each of the Transforms, the item’s AVPL will be operated against the Transform’s Match clauses starting from the topmost one, until all have been tried or until one of them succeeds.

MATE’s Transforms can be used for many different things, like:

12.3.4.6.1. Multiple Start/Stop conditions for a Gop

Using Transforms we can add more than one start or stop condition to a Gop.

Transform start_cond {
  Match (attr1=aaa,attr2=bbb) (msg_type=start);
  Match (attr3=www,attr2=bbb) (msg_type=start);
  Match (attr5^a) (msg_type=stop);
  Match (attr6$z) (msg_type=stop);
};

Pdu pdu ... {
  ...
  Transform start_cond;
}

Gop gop ... {
  Start (msg_type=start);
  Stop (msg_type=stop);
  ...
}
12.3.4.6.2. Marking Gops and Gogs to filter them easily
Transform marks {
  Match (addr=10.10.10.10, user=john) (john_at_host);
  Match (addr=10.10.10.10, user=tom) (tom_at_host);
}

...

Gop my_gop ... {
  ...
  Transform marks;
}

After that we can use a display filter mate.gop.john_at_host or mate.gop.tom_at_host

12.3.4.6.3. Adding direction knowledge to MATE
Transform direction_as_text {
  Match (src=192.168.0.2, dst=192.168.0.3) Replace (direction=from_2_to_3);
  Match (src=192.168.0.3, dst=192.168.0.2) Replace (direction=from_3_to_2);
};

Pdu my_pdu Proto my_proto Transport tcp/ip {
  Extract src From ip.src;
  Extract dst From ip.dst;
  Extract addr From ip.addr;
  Extract port From tcp.port;
  Extract start From tcp.flags.syn;
  Extract stop From tcp.flags.fin;
  Extract stop From tcp.flags.rst;
  Transform direction_as_text;
}

Gop my_gop On my_pdu Match (addr,addr,port,port) {
  ...
  Extra (direction);
}
12.3.4.6.4. NAT

NAT can create problems when tracing, but we can easily worked around it by Transforming the NATed IP address and the Ethernet address of the router into the non-NAT address:

Transform denat {
  Match (addr=192.168.0.5, ether=01:02:03:04:05:06) Replace (addr=123.45.67.89);
  Match (addr=192.168.0.6, ether=01:02:03:04:05:06) Replace (addr=123.45.67.90);
  Match (addr=192.168.0.7, ether=01:02:03:04:05:06) Replace (addr=123.45.67.91);
}

Pdu my_pdu Proto my_proto transport tcp/ip/eth {
  Extract ether From eth.addr;
  Extract addr From ip.addr;
  Extract port From tcp.port;
  Transform denat;
}

12.3.5. About MATE

MATE was originally written by Luis Ontanon, a Telecomunications systems troubleshooter, as a way to save time filtering out the packets of a single call from huge capture files using just the calling number. Later he used the time he had saved to make it flexible enough to work with protocols other than the ones he was directly involved with.

12.4. MATE’s configuration tutorial

We’ll show a MATE configuration that first creates Gops for every DNS and HTTP request, then it ties the Gops together in a Gop based on the host. Finally we’ll separate into different Gogs request coming from different users.

With this MATE configuration loaded we can:

  • use mate.http_use.Duration > 5.5 to filter frames based on the time it takes to load a complete page from the DNS request to resolve its name until the last image gets loaded.
  • use mate.http_use.client == "10.10.10.20" && mate.http_use.host == "www.example.com" to isolate DNS and HTTP packets related to a visit of a certain user.
  • use mate.http_req.Duration > 1.5 to filter all the packets of HTTP requests that take more than 1.5 seconds to complete.

The complete config file is here: web.mate

Note: for this example I used dns.qry.name which is defined since Wireshark version 0.10.9. Supposing you have a mate plugin already installed you can test it with the current Wireshark version.

12.4.1. A Gop for DNS requests

First we’ll tell MATE how to create a Gop for each DNS request/response.

MATE needs to know what makes a DNS PDU. We describe it this using a Pdu declaration:

Pdu dns_pdu Proto dns Transport ip {
  Extract addr From ip.addr;
  Extract dns_id From dns.id;
  Extract dns_resp From dns.flags.response;
};

Using Proto dns we tell MATE to create Pdus every time it finds dns. Using Transport ip we inform MATE that some of the fields we are interested are in the ip part of the frame. Finally, we tell MATE to import ip.addr as addr, dns.id as dns_id and dns.flags.response as dns_resp.

Once we’ve told MATE how to extract dns_pdus we’ll tell it how to match requests and responses and group them into a Gop. For this we’ll use a Gop declaration to define the Gop, and then, Start and Stop statements to tell it when the Gop starts and ends.

Gop dns_req On dns_pdu Match (addr,addr,dns_id) {
  Start (dns_resp=0);
  Stop (dns_resp=1);
};

Using the Gop declaration we tell MATE that the Name of the Gop is dns_req, that dns_pdus can become members of the Gop, and what is the key used to match the Pdus to the Gop.

The key for this Gop is "addr, addr, dns_id". That means that in order to belong to the same Gop, dns_pdus have to have both addresses and the request id identical. We then instruct MATE that a dns_req starts whenever a dns_pdu matches "dns_resp=0" and that it stops when another dns_pdu matches "dns_resp=1".

At this point, if we open a capture file using this configuration, we are able to use a display filter mate.dns_req.Time > 1 to see only the packets of DNS requests that take more than one second to complete.

We can use a display filter mate.dns_req && ! mate.dns_req.Time to find requests for which no response was given. mate.xxx.Time is set only for Gops that have being stopped.

12.4.2. A Gop for HTTP requests

This other example creates a Gop for every HTTP request.

Pdu http_pdu Proto http Transport tcp/ip {
  Extract addr From ip.addr;
  Extract port From tcp.port;
  Extract http_rq From http.request.method;
  Extract http_rs From http.response;
  DiscardPduData true;
};

Gop http_req On http_pdu Match (addr, addr, port, port) {
  Start (http_rq);
  Stop (http_rs);
};

So, if we open a capture using this configuration

  • filtering with mate.http_req.Time > 1 will give all the requests where the response header takes more than one second to come
  • filtering with mate.http_req.Duration > 1.5 will show those request that take more than 1.5 seconds to complete.

You have to know that mate.xxx.Time gives the time in seconds between the pdu matching the GopStart and the Pdu matching the GopStop (yes, you can create timers using this!). On the other hand, mate.xxx.Duration gives you the time passed between the GopStart and the last pdu assigned to that Gop regardless whether it is a stop or not. After the GopStop, Pdus matching the Gop’s Key will still be assigned to the same Gop as far as they don’t match the GopStart, in which case a new Gop with the same key will be created.

12.4.3. Getting DNS and HTTP together into a Gog

We’ll tie together to a single Gog all the http packets belonging to requests and responses to a certain host and the dns request and response used to resolve its domain name using the Pdu and Gop definitions of the previous examples

To be able to group DNS and HTTP requests together, we need to import into the Pdus and Gops some part of information that both those protocols share. Once the Pdus and Gops have been defined, we can use Extract (for Pdus) and Extract (for Gops) statements to tell MATE what other protocol fields are to be added to Pdus' and Gops' AVPLs. We add the following statements to the appropriate declarations:

Extract host From http.host; // to Pdu http_pdu as the last Extract in the list
Extra (host); // to Gop http_req after the Stop

Extract host From dns.qry.name; // to Pdu dns_pdu as the last Extract in the list
Extra (host); // to Gop dns_req after the Stop

Here we’ve told MATE to import http.host into http_pdu and dns.qry.name into dns_pdu as host. We also have to tell MATE to copy the host attribute from the Pdus to the Gops, we do this using Extra.

Once we’ve got all the data we need in Pdus and Gops, we tell MATE what makes different Gops belong to a certain Gog.

Gog http_use {
  Member http_req (host);
  Member dns_req (host);
  Expiration 0.75;
};

Using the Gog declaration we tell MATE to define a Gog type Named http_use whose expiration is 0.75 seconds after all the Gops that belong to it had been stopped. After that time, an eventual new Gop with the same key match will create a new Gog instead of been added to the previous Gog.

Using the Member statements we tell MATE that http_req*s with the same *host belong to the same Gog, same thing for *dns_req*s.

So far we have instructed mate to group every packet related to sessions towards a certain host. At this point if we open a capture file and:

  • a display filter mate.http_use.Duration > 5 will show only those requests that have taken more than 5 seconds to complete starting from the DNS request and ending with the last packet of the http responses.
  • a display filter mate.http_use.host == "www.w3c.org" will show all the packets (both DNS and HTTP) related to the requests directed to www.w3c.org

12.4.4. Separating requests from multiple users

"Houston: we’ve had a problem here."

This configuration works fine if used for captures taken at the client’s side but deeper in the network we’d got a real mess. Requests from many users get mixed together into http_uses. Gogs are created and stopped almost randomly (depending on the timing in which Gops start and stop). How do we get requests from individual users separated from each other?

MATE has a tool that can be used to resolve this kind of grouping issues. This tool are the Transforms. Once defined, they can be applied against Pdus, Gops and Gogs and they might replace or insert more attributes based on what’s there. We’ll use them to create an attribute named client, using which we’ll separate different requests.

For DNS we need the ip.src of the request moved into the Gop only from the DNS request.

So we first tell MATE to import ip.src as client:

Extract client From ip.src;

Next, we tell MATE to replace ( dns_resp=1, client ) with just dns_resp=1 in the Pdu. That way, we’ll keep the attribute client only in the DNS request Pdus (i.e. packets coming from the client).To do so, we have to add a Transform declaration (in this case, with just one clause) before the Pdu declaration which uses it:

Transform rm_client_from_dns_resp {
  Match (dns_resp=1, client) Replace (dns_resp=1);
};

Next, we invoke the transform by adding the following line after the Extract list of the dns_pdu Pdu:

  Transform rm_client_from_dns_resp;

HTTP is a little trickier. We have to remove the attribute carrying ip.src from both the response and the "continuations" of the response, but as there is nothing to filter on for the continuations, we have to add a fake attribute first. And then we have to remove client when the fake attribute appears. This is possible due to the fact that the Match clauses in the Transform are executed one by one until one of them succeeds. First, we declare another two Transforms:

Transform rm_client_from_http_resp1 {
  Match (http_rq); //first match wins so the request won't get the not_rq attribute inserted
  Match Every (addr) Insert (not_rq); //this line won't be evaluated if the first one matched so not_rq won't be inserted to requests
};

Transform rm_client_from_http_resp2 {
  Match (not_rq, client) Replace (); //replace "client and not_rq" with nothing (will happen only in the response and eventual parts of it)
};

Next, we add another Extract statement to the http_pdu declaration, and apply both Transforms declared above in a proper order:

  Extract client From ip.src;
  Transform rm_client_from_http_resp1, rm_client_from_http_resp2;

In MATE, all the Transform+s listed for an item will be evaluated, while inside a single +Transform, the evaluation will stop at the first successful Match clause. That’s why we first just match http_rq to get out of the first sequence before adding the not_rq attribute. Then we apply the second Transform which removes both not_rq and client if both are there. Yes, +Transform+s are cumbersome, but they are very useful.

Once we got all what we need in the Pdus, we have to tell MATE to copy the attribute client from the Pdus to the respective Gops, by adding client to Extra lists of both Gop declarations:

Extra (host, client);

On top of that, we need to modify the old declarations of Gop key to new ones that include both client and host. So we change the Gog Member declarations the following way:

  Member http_req (host, client);
  Member dns_req (host, client);

Now we got it, every "usage" gets it’s own Gog.

12.5. MATE configuration examples

The following is a collection of various configuration examples for MATE. Many of them are useless because the "conversations" facility does a better job. Anyway they are meant to help users understanding how to configure MATE.

12.5.1. TCP session

The following example creates a GoP out of every TCP session.

Pdu tcp_pdu Proto tcp Transport ip {
    Extract addr From ip.addr;
    Extract port From tcp.port;
    Extract tcp_start From tcp.flags.syn;
    Extract tcp_stop From tcp.flags.reset;
    Extract tcp_stop From tcp.flags.fin;
};

Gop tcp_ses On tcp_pdu Match (addr, addr, port, port) {
    Start (tcp_start=1);
    Stop (tcp_stop=1);
};

Done;

This probably would do fine in 99.9% of the cases but 10.0.0.1:20→10.0.0.2:22 and 10.0.0.1:22→10.0.0.2:20 would both fall into the same gop if they happen to overlap in time.

  • filtering with mate.tcp_ses.Time > 1 will give all the sessions that last less than one second
  • filtering with mate.tcp_ses.NumOfPdus < 5 will show all tcp sessions that have less than 5 packets.
  • filtering with mate.tcp_ses.Id == 3 will show all the packets for the third tcp session MATE has found

12.5.2. a Gog for a complete FTP session

This configuration allows to tie a complete passive ftp session (including the data transfer) in a single Gog.

Pdu ftp_pdu Proto ftp Transport tcp/ip {
        Extract ftp_addr From ip.addr;
        Extract ftp_port From tcp.port;
        Extract ftp_resp From ftp.response.code;
        Extract ftp_req From ftp.request.command;
        Extract server_addr From ftp.passive.ip;
        Extract server_port From ftp.passive.port;

        LastPdu;
};

Pdu ftp_data_pdu Proto ftp-data Transport tcp/ip{
        Extract server_addr From ip.src;
        Extract server_port From tcp.srcport;

};

Gop ftp_data On ftp_data_pdu (server_addr, server_port) {
        Start (server_addr);
};

Gop ftp_ctl On ftp_pdu (ftp_addr, ftp_addr, ftp_port, ftp_port) {
        Start (ftp_resp=220);
        Stop (ftp_resp=221);
        Extra (server_addr, server_port);
};

Gog ftp_ses {
        Member ftp_ctl (ftp_addr, ftp_addr, ftp_port, ftp_port);
        Member ftp_data (server_addr, server_port);
};

Done;

Note: not having anything to distinguish between ftp-data packets makes this config to create one Gop for every ftp-data packet instead of each transfer. Pre-started Gops would avoid this.

12.5.3. using RADIUS to filter SMTP traffic of a specific user

Spying on people, in addition to being immoral, is illegal in many countries. This is an example meant to explain how to do it not an invitation to do so. It’s up to the police to do this kind of job when there is a good reason to do so.

Pdu radius_pdu On radius Transport udp/ip {
    Extract addr From ip.addr;
    Extract port From udp.port;
    Extract radius_id From radius.id;
    Extract radius_code From radius.code;
    Extract user_ip From radius.framed_addr;
    Extract username From radius.username;
}

Gop radius_req On radius_pdu (radius_id, addr, addr, port, port) {
    Start (radius_code {1|4|7} );
    Stop (radius_code {2|3|5|8|9} );
    Extra (user_ip, username);
}

// we define the smtp traffic we want to filter
Pdu user_smtp Proto smtp Transport tcp/ip {
    Extract user_ip From ip.addr;
    Extract smtp_port From tcp.port;
    Extract tcp_start From tcp.flags.syn;
    Extract tcp_stop From tcp.flags.reset;
}

Gop user_smtp_ses On user_smtp (user_ip, user_ip, smtp_port!25) {
    Start (tcp_start=1);
    Stop (tcp_stop=1);
}

// with the following group of groups we'll group toghether the radius and the smtp
// we set a long expiration to avoid the session expire on long pauses.
Gog user_mail {
    Expiration 1800;
    Member radius_req (user_ip);
    Member user_smtp_ses (user_ip);
    Extra (username);
}

Done;

Filtering the capture file with mate.user_mail.username == "theuser" will filter the radius packets and smtp traffic for "theuser".

12.5.4. H323 Calls

This configuration will create a Gog out of every call.

Pdu q931 Proto q931 Transport ip {
        Extract addr From ip.addr;
        Extract call_ref From q931.call_ref;
        Extract q931_msg From q931.message_type;
        Extract calling From q931.calling_party_number.digits;
        Extract called From q931.called_party_number.digits;
        Extract guid From h225.guid;
        Extract q931_cause From q931.cause_value;
};

Gop q931_leg On q931 Match (addr, addr, call_ref) {
        Start (q931_msg=5);
        Stop (q931_msg=90);
        Extra (calling, called, guid, q931_cuase);
};

Pdu ras Proto h225.RasMessage Transport ip {
        Extract addr From ip.addr;
        Extract ras_sn From h225.requestSeqNum;
        Extract ras_msg From h225.RasMessage;
        Extract guid From h225.guid;
};

Gop ras_req On ras Match (addr, addr, ras_sn) {
        Start (ras_msg {0|3|6|9|12|15|18|21|26|30} );
        Stop (ras_msg {1|2|4|5|7|8|10|11|13|14|16|17|19|20|22|24|27|28|29|31});
        Extra (guid);
};

Gog call {
        Member ras_req (guid);
        Member q931_leg (guid);
        Extra (called,calling,q931_cause);
};

Done;

with this we can:

  • filter all signalling for a specific caller: mate.call.caller == "123456789"
  • filter all signalling for calls with a specific release cause: mate.call.q931_cause == 31
  • filter all signalling for very short calls: mate.q931_leg.Time < 5

12.5.5. MMS

With this example, all the components of an MMS send or receive will be tied into a single Gog. Note that this example uses the Payload clause because MMS delivery uses MMSE over either HTTP or WSP. As it is not possible to relate the retrieve request to a response by the means of MMSE only (the request is just an HTTP GET without any MMSE), a Gop is made of HTTP Pdus but MMSE data need to be extracted from the bodies.

## WARNING: this example has been blindly translated from the "old" MATE syntax
## and it has been verified that Wireshark accepts it. However, it has not been
## tested against any capture file due to lack of the latter.

Transform rm_client_from_http_resp1 {
        Match (http_rq);
        Match Every (addr) Insert (not_rq);
};

Transform rm_client_from_http_resp2 {
        Match (not_rq,ue) Replace ();
};

Pdu mmse_over_http_pdu Proto http Transport tcp/ip {
        Payload mmse;
        Extract addr From ip.addr;
        Extract port From tcp.port;
        Extract http_rq From http.request;
        Extract content From http.content_type;
        Extract resp From http.response.code;
        Extract method From http.request.method;
        Extract host From http.host;
        Extract content From http.content_type;
        Extract trx From mmse.transaction_id;
        Extract msg_type From mmse.message_type;
        Extract notify_status From mmse.status;
        Extract send_status From mmse.response_status;
        Transform rm_client_from_http_resp1, rm_client_from_http_resp2;
};

Gop mmse_over_http On mmse_over_http_pdu Match (addr, addr, port, port) {
        Start (http_rq);
        Stop (http_rs);
        Extra (host, ue, resp, notify_status, send_status, trx);
};

Transform mms_start {
        Match Loose() Insert (mms_start);
};

Pdu mmse_over_wsp_pdu Proto wsp Transport ip {
        Payload mmse;
        Extract trx From mmse.transaction_id;
        Extract msg_type From mmse.message_type;
        Extract notify_status From mmse.status;
        Extract send_status From mmse.response_status;
        Transform mms_start;
};

Gop mmse_over_wsp On mmse_over_wsp_pdu Match (trx) {
        Start (mms_start);
        Stop (never);
        Extra (ue, notify_status, send_status);
};

Gog mms {
        Member mmse_over_http (trx);
        Member mmse_over_wsp (trx);
        Extra (ue, notify_status, send_status, resp, host, trx);
        Expiration 60.0;
};

12.6. MATE’s configuration library

The MATE library (will) contains GoP definitions for several protocols. Library protocols are included in your MATE config using: Action=Include; Lib=proto_name;.

For Every protocol with a library entry, we’ll find defined what from the PDU is needed to create a GoP for that protocol, eventually any criteria and the very essential GoP definition (i.e. GopDef, GopStart and GopStop).

[Note] Note

It seems that this code is written in the old syntax of MATE. So far it has not been transcribed into the new format. It may still form the basis to recreate these in the new format.

12.6.1. General use protocols

12.6.1.1. TCP

It will create a GoP for every TCP session, If it is used it should be the last one in the list. And every other proto on top of TCP should be declared with Stop=TRUE; so the a TCP PDU is not created where we got already one going on.

   Action=PduDef; Name=tcp_pdu; Proto=tcp; Transport=ip; addr=ip.addr; port=tcp.port; tcp_start=tcp.flags.syn; tcp_stop=tcp.flags.fin; tcp_stop=tcp.flags.reset;
   Action=GopDef; Name=tcp_session; On=tcp_pdu; addr; addr; port; port;
   Action=GopStart; For=tcp_session; tcp_start=1;
   Action=GopStop; For=tcp_session; tcp_stop=1;

12.6.1.2. DNS

will create a GoP containing every request and it’s response (eventually retransmissions too).

Action=PduDef; Name=dns_pdu; Proto=dns; Transport=udp/ip; addr=ip.addr; port=udp.port; dns_id=dns.id; dns_rsp=dns.flags.response;

Action=GopDef; Name=dns_req; On=dns_pdu; addr; addr; port!53; dns_id;
Action=GopStart; For=dns_req; dns_rsp=0;
Action=GopStop; For=dns_req; dns_rsp=1;

12.6.1.3. RADIUS

A Gop for every transaction.

Action=PduDef; Name=radius_pdu; Proto=radius; Transport=udp/ip; addr=ip.addr; port=udp.port; radius_id=radius.id; radius_code=radius.code;

Action=GopDef; Name=radius_req; On=radius_pdu; radius_id; addr; addr; port; port;
Action=GopStart; For=radius_req; radius_code|1|4|7;
Action=GopStop; For=radius_req; radius_code|2|3|5|8|9;

12.6.1.4. RTSP

Action=PduDef; Name=rtsp_pdu; Proto=rtsp; Transport=tcp/ip; addr=ip.addr; port=tcp.port; rtsp_method=rtsp.method;
Action=PduExtra; For=rtsp_pdu; rtsp_ses=rtsp.session; rtsp_url=rtsp.url;

Action=GopDef; Name=rtsp_ses; On=rtsp_pdu; addr; addr; port; port;
Action=GopStart; For=rtsp_ses; rtsp_method=DESCRIBE;
Action=GopStop; For=rtsp_ses; rtsp_method=TEARDOWN;
Action=GopExtra; For=rtsp_ses; rtsp_ses; rtsp_url;

12.6.2. VoIP/Telephony

Most protocol definitions here will create one Gop for every Call Leg unless stated.

12.6.2.1. ISUP

Action=PduDef; Name=isup_pdu; Proto=isup; Transport=mtp3; mtp3pc=mtp3.dpc; mtp3pc=mtp3.opc; cic=isup.cic; isup_msg=isup.message_type;

Action=GopDef; Name=isup_leg; On=isup_pdu; ShowPduTree=TRUE; mtp3pc; mtp3pc; cic;
Action=GopStart; For=isup_leg; isup_msg=1;
Action=GopStop; For=isup_leg; isup_msg=16;

12.6.2.2. Q931

Action=PduDef; Name=q931_pdu; Proto=q931; Stop=TRUE; Transport=tcp/ip; addr=ip.addr; call_ref=q931.call_ref; q931_msg=q931.message_type;

Action=GopDef; Name=q931_leg; On=q931_pdu; addr; addr; call_ref;
Action=GopStart; For=q931_leg; q931_msg=5;
Action=GopStop; For=q931_leg; q931_msg=90;

12.6.2.3. H225 RAS

Action=PduDef; Name=ras_pdu; Proto=h225.RasMessage; Transport=udp/ip; addr=ip.addr; ras_sn=h225.RequestSeqNum; ras_msg=h225.RasMessage;
Action=PduExtra; For=ras_pdu; guid=h225.guid;

Action=GopDef; Name=ras_leg; On=ras_pdu; addr; addr; ras_sn;
Action=GopStart; For=ras_leg; ras_msg|0|3|6|9|12|15|18|21|26|30;
Action=GopStop; For=ras_leg; ras_msg|1|2|4|5|7|8|10|11|13|14|16|17|19|20|22|24|27|28|29|31;
Action=GopExtra; For=ras_leg; guid;

12.6.2.4. SIP

Action=PduDef; Proto=sip_pdu; Transport=tcp/ip; addr=ip.addr; port=tcp.port; sip_method=sip.Method; sip_callid=sip.Call-ID; calling=sdp.owner.username;

Action=GopDef; Name=sip_leg; On=sip_pdu; addr; addr; port; port;
Action=GopStart; For=sip; sip_method=INVITE;
Action=GopStop; For=sip; sip_method=BYE;

12.6.2.5. MEGACO

Will create a Gop out of every transaction.

To "tie" them to your call’s GoG use: Action=GogKey; Name=your_call; On=mgc_tr; addr!mgc_addr; megaco_ctx;

Action=PduDef; Name=mgc_pdu; Proto=megaco; Transport=ip; addr=ip.addr; megaco_ctx=megaco.context; megaco_trx=megaco.transid; megaco_msg=megaco.transaction; term=megaco.termid;

Action=GopDef; Name=mgc_tr; On=mgc_pdu; addr; addr; megaco_trx;
Action=GopStart; For=mgc_tr; megaco_msg|Request|Notify;
Action=GopStop; For=mgc_tr; megaco_msg=Reply;
Action=GopExtra; For=mgc_tr; term^DS1; megaco_ctx!Choose one;

12.7. MATE’s reference manual

12.7.1. Attribute Value Pairs

MATE uses AVPs for almost everything: to keep the data it has extracted from the frames' trees as well as to keep the elements of the configuration.

These "pairs" (actually tuples) are made of a name, a value and, in case of configuration AVPs, an operator. Names and values are strings. AVPs with operators other than = are used only in the configuration and are used for matching AVPs of Pdus, GoPs and GoGs in the analysis phase.

12.7.1.1. Name

The name is a string used to refer to a class of AVPs. Two attributes won’t match unless their names are identical. Capitalized names are reserved for keywords (you can use them for your elements if you want but I think it’s not the case). MATE attribute names can be used in Wireshark’s display filters the same way like names of protocol fields provided by dissectors, but they are not just references to (or aliases of) protocol fields.

12.7.1.2. Value

The value is a string. It is either set in the configuration (for configuration AVPs) or by MATE while extracting interesting fields from a dissection tree and/or manipulating them later. The values extracted from fields use the same representation as they do in filter strings.

12.7.1.3. Operators

Currently only match operators are defined (there are plans to (re)add transform attributes but some internal issues have to be solved before that). The match operations are always performed between two operands: the value of an AVP stated in the configuration and the value of an AVP (or several AVPs with the same name) extracted from packet data (called "data AVPs"). It is not possible to match data AVPs to each other.

The defined match operators are:

  • Equal = test for equality, that is: either the value strings are identical or the match will fail.
  • Not Equal ! will match only if the value strings aren’t equal.
  • One Of {} will match if one of the value strings listed is equal to the data AVP’s string. Individual tems of the list inside the curly braces are separated using | character.
  • Starts With ^ will match if the configuration value string matches the first characters of the data AVP’s value string.
  • Ends With $ will match if the configuration value string matches the last characters of the data AVP’s value string.
  • Contains ~ will match if the configuration value string matches a substring of the characters of the data AVP’s value string.
  • Lower Than < will match if the data AVP’s value string is semantically lower than the configuration value string.
  • Higher Than > will match if the data AVP’s value string is semantically higher than the configuration value string.
  • Exists ? (can be omitted) will match if the AVP name matches, regardless what the value string is.
12.7.1.3.1. Equal AVP Operator

This operator tests whether the values of the operator and the operand AVP are equal.

Example
attrib=aaa matches attrib=aaa attrib=aaa does not match attrib=bbb
12.7.1.3.2. Not equal AVP operator

This operator matches if the value strings of two AVPs are not equal.

Example
attrib=aaa matches attrib!bbb attrib=aaa does not match attrib!aaa
12.7.1.3.3. "One of" AVP operator

The "one of" operator matches if the data AVP value is equal to one of the values listed in the "one of" AVP.

Example
attrib=1 matches attrib{1|2|3} attrib=2 matches attrib{1|2|3} attrib=4 does not match attrib{1|2|3}
12.7.1.3.4. "Starts with" AVP operator

The "starts with" operator matches if the first characters of the data AVP value are identical to the configuration AVP value.

Example
attrib=abcd matches attrib^abc attrib=abc matches attrib^abc attrib=ab does not match attrib^abc attrib=abcd does not match attrib^bcd attrib=abc does not match attrib^abcd
12.7.1.3.5. "Ends with" operator

The ends with operator will match if the last bytes of the data AVP value are equal to the configuration AVP value.

Example
attrib=wxyz matches attrib$xyz attrib=yz does not match attrib$xyz attrib=abc…​wxyz does not match attrib$abc
12.7.1.3.6. Contains operator

The "contains" operator will match if the data AVP value contains a string identical to the configuration AVP value.

Example
attrib=abcde matches attrib~bcd attrib=abcde matches attrib~abc attrib=abcde matches attrib~cde attrib=abcde does not match attrib~xyz
12.7.1.3.7. "Lower than" operator

The "lower than" operator will match if the data AVP value is semantically lower than the configuration AVP value.

Example
attrib=abc matches attrib<bcd attrib=1 matches attrib<2 but beware: attrib=10 does not match attrib<9 attrib=bcd does not match attrib<abc attrib=bcd does not match attrib<bcd

BUGS

It should check whether the values are numbers and compare them numerically

12.7.1.3.8. "Higher than" operator

The "higher than" operator will match if the data AVP value is semantically higher than the configuration AVP value.

Examples

attrib=bcd matches attrib>abc attrib=3 matches attrib>2 but beware: attrib=9 does not match attrib>10 attrib=abc does not match attrib>bcd attrib=abc does not match attrib>abc

BUGS

It should check whether the values are numbers and compare them numerically

12.7.1.3.9. Exists operator

The exists operator will always match as far as the two operands have the same name.

Examples

attrib=abc matches attrib? attrib=abc matches attrib (this is just an alternative notation of the previous example) obviously attrib=abc does not match other_attrib?

12.7.2. Attribute/Value Pair List (AVPL)

Pdus, GoPs and GoGs use an AVPL to contain the tracing information. An AVPL is an unsorted set of AVPs that can be matched against other AVPLs.

12.7.2.1. Operations between AVPLs

There are three types of match operations that can be performed between AVPLs. The Pdu’s/GoP’s/GoG’s AVPL will be always one of the operands; the AVPL operator (match type) and the second operand AVPL will always come from the configuration. Note that a diverse AVP match operator may be specified for each AVP in the configuration AVPL.

An AVPL match operation returns a result AVPL. In Transforms, the result AVPL may be replaced by another AVPL. The replacement means that the existing data AVPs are dropped and the replacement AVPL from the configuration is Merged to the data AVPL of the Pdu/GoP/GoG.

  • Loose Match: Will match if at least one of the AVPs of the two operand AVPLs match. If it matches, it returns a result AVPL containing all AVPs from the data AVPL that did match the configuration’s AVPs.
  • "Every" Match: Will match if none of the AVPs of the configuration AVPL fails to match an AVP in the data AVPL, even if not all of the configuration AVPs have a match. If it matches, it returns a result AVPL containing all AVPs from the data AVPL that did match an AVP in the configuration AVPL.
  • Strict Match: Will match if and only if each of the AVPs in the configuration AVPL has at least one match in the data AVPL. If it matches, it returns a result AVPL containing those AVPs from the data AVPL that matched.
12.7.2.1.1. Loose Match

A loose match between AVPLs succeeds if at least one of the data AVPs matches at least one of the configuration AVPs. Its result AVPL contains all the data AVPs that matched.

Loose matches are used in Extra operations against the Pdu's AVPL to merge the result into Gop's AVPL, and against Gop's AVPL to merge the result into Gog's AVPL. They may also be used in Criteria and Transforms.

[Note] Note

As of current (2.0.1), Loose Match does not work as described here, see Bug 12184. Only use in Transforms and Criteria is effectively affected by the bug.

Loose Match Examples

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a?, attr_c?) =⇒ (attr_a=aaa, attr_c=xxx)

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a?, attr_c=ccc) =⇒ (attr_a=aaa)

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a=xxx; attr_c=ccc) =⇒ No Match!

12.7.2.1.2. Every Match

An "every" match between AVPLs succeeds if none of the configuration’s AVPs that have a counterpart in the data AVPL fails to match. Its result AVPL contains all the data AVPs that matched.

These may only be used in Criteria and Transforms.

[Note] Note

As of current (2.0.1), Loose Match does not work as described here, see Bug 12184.

"Every" Match Examples

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c?) =⇒ (attr_a=aaa, attr_c=xxx)

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c?, attr_d=ddd) =⇒ (attr_a=aaa, attr_c=xxx)

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c=ccc) =⇒ No Match!

(attr_a=aaa; attr_b=bbb; attr_c=xxx) Match Every (attr_a=xxx, attr_c=ccc) =⇒ No Match!

12.7.2.1.3. Strict Match

A Strict match between AVPLs succeeds if and only if every AVP in the configuration AVPL has at least one counterpart in the data AVPL and none of the AVP matches fails. The result AVPL contains all the data AVPs that matched.

These are used between Gop keys (key AVPLs) and Pdu AVPLs. They may also be used in Criteria and Transforms.

Examples

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c=xxx) =⇒ (attr_a=aaa, attr_c=xxx)

(attr_a=aaa, attr_b=bbb, attr_c=xxx, attr_c=yyy) Match Strict (attr_a?, attr_c?) =⇒ (attr_a=aaa, attr_c=xxx, attr_c=yyy)

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c=ccc) =⇒ No Match!

(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c?, attr_d?) =⇒ No Match!

12.7.2.1.4. AVPL Merge

An AVPL may be merged into another one. That would add to the latter every AVP from the former that does not already exist there.

This operation is done

  • between the result of a key match and the Gop’s or Gog’s AVPL,
  • between the result of an Extra match and the Gop’s or Gog’s AVPL,
  • between the result of a Transform match and Pdu’s/Gop’s AVPL. If the operation specified by the Match clause is Replace, the result AVPL of the match is removed from the item’s AVPL before the modify_avpl is merged into it.

Examples

(attr_a=aaa, attr_b=bbb) Merge (attr_a=aaa, attr_c=xxx) former becomes (attr_a=aaa, attr_b=bbb, attr_c=xxx)

(attr_a=aaa, attr_b=bbb) Merge (attr_a=aaa, attr_a=xxx) former becomes (attr_a=aaa, attr_a=xxx, attr_b=bbb)

(attr_a=aaa, attr_b=bbb) Merge (attr_c=xxx, attr_d=ddd) former becomes (attr_a=aaa, attr_b=bbb, attr_c=xxx, attr_d=ddd)

12.7.2.1.5. Transforms

A Transform is a sequence of Match rules optionally followed by an instruction how to modify the match result using an additional AVPL. Such modification may be an Insert (merge) or a Replace. The syntax is as follows:

Transform name {
    Match [Strict|Every|Loose] match_avpl [[Insert|Replace] modify_avpl] ; // may occur multiple times, at least once
};

For examples of Transforms, check the Manual page.

TODO: migrate the examples here?

The list of Match rules inside a Transform is processed top to bottom; the processing ends as soon as either a Match rule succeeds or all have been tried in vain.

Transforms can be used as helpers to manipulate an item’s AVPL before the item is processed further. An item declaration may contain a Transform clause indicating a list of previously declared Transforms. Regardless whether the individual transforms succeed or fail, the list is always executed completely and in the order given, i.e. left to right.

In MATE configuration file, a Transform must be declared before declaring any item which uses it.

12.8. Configuration AVPLs

12.8.1. Pdsu’s configuration actions

The following configuration AVPLs deal with PDU creation and data extraction.

12.8.1.1. Pdu declaration block header

In each frame of the capture, MATE will look for source proto_name's PDUs in the order in which the declarations appear in its configuration and will create Pdus of every type it can from that frame, unless specifically instructed that some Pdu type is the last one to be looked for in the frame. If told so for a given type, MATE will extract all Pdus of that type and the previously declared types it finds in the frame but not those declared later.

The complete declaration of a Pdu looks as below; the mandatory order of the diverse clauses is as shown.

    Pdu name Proto proto_name Transport proto1[/proto2/proto3[/...]]] {
      Payload proto; //optional, no default value
      Extract attribute From proto.field ; //may occur multiple times, at least once
      Transform (transform1[, transform2[, ...]]); //optional
      Criteria [{Accept|Reject}] [{Strict|Every|Loose} match_avpl];
      DropUnassigned {true|false}; //optional, default=false
      DiscardPduData {true|false}; //optional, default=false
      LastExtracted {true|false}; //optional, default=false
    };

12.8.1.2. Pdu name

The name is a mandatory attribute of a Pdu declaration. It is chosen arbitrarily, except that each name may only be used once in MATE’s configuration, regardless the class of an item it is used for. The name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as part of the filterable fields' names related to this type of Pdu which MATE creates.

However, several Pdu declarations may share the same name. In such case, all of them are created from each source PDU matching their Proto, Transport, and Payload clauses, while the bodies of their declarations may be totally different from each other. Together with the Accept (or Reject) clauses, this feature is useful when it is necessary to build the Pdu’s AVPL from different sets of source fields depending on contents (or mere presence) of other source fields.

12.8.1.2.1. Proto and Transport clauses

Every instance of the protocol proto_name PDU in a frame will generate one Pdu with the AVPs extracted from fields that are in the proto_name's range and/or the ranges of underlying protocols specified by the Transport list. It is a mandatory attribute of a Pdu declaration. The proto_name is the name of the protocol as used in Wireshark display filter.

The Pdu’s Proto, and its Transport list of protocols separated by / tell MATE which fields of a frame can get into the Pdu’s AVPL. In order that MATE would extract an attribute from a frame’s protocol tree, the area representing the field in the hex display of the frame must be within the area of either the Proto or it’s relative Transport s. Transport s are chosen moving backwards from the protocol area, in the order they are given.

Proto http Transport tcp/ip does what you’d expect it to - it selects the nearest tcp range that precedes the current http range, and the nearest ip range that precedes that tcp range. If there is another ip range before the nearest one (e.g. in case of IP tunneling), that one is not going to be selected. Transport tcp/ip/ip that "logically" should select the encapsulating IP header too doesn’t work so far.

Once we’ve selected the Proto and Transport ranges, MATE will fetch those protocol fields belonging to them whose extraction is declared using the Extract clauses for the Pdu type. The Transport list is also mandatory, if you actually don’t want to use any transport protocol, use Transport mate. (This didn’t work until 0.10.9).

12.8.1.2.2. Payload clause

Other than the Pdu’s Proto and its Transport protocols, there is also a Payload attribute to tell MATE from which ranges of Proto's payload to extract fields of a frame into the Pdu. In order to extract an attribute from a frame’s tree the highlighted area of the field in the hex display must be within the area of the Proto's relative payload(s). Payload s are choosen moving forward from the protocol area, in the order they are given. Proto http Transport tcp/ip Payload mmse will select the first mmse range after the current http range. Once we’ve selected the Payload ranges, MATE will fetch those protocol fields belonging to them whose extraction is declared using the Extract clauses for the Pdu type.

12.8.1.2.3. Extract clause

Each Extract clause tells MATE which protocol field value to extract as an AVP value and what string to use as the AVP name. The protocol fields are referred to using the names used in Wireshark display filters. If there is more than one such protocol field in the frame, each instance that fulfills the criteria stated above is extracted into its own AVP. The AVP names may be chosen arbitrarily, but to be able to match values originally coming from different Pdus (e.g., hostname from DNS query and a hostname from HTTP GET request) later in the analysis, identical AVP names must be assigned to them and the dissectors must provide the field values in identical format (which is not always the case).

12.8.1.2.4. Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Pdu’s AVPL after all protocol fields have been extracted to it. The list is always executed completely, left to right. On the contrary, the list of Match clauses inside each individual Transform is executed only until the first match succeeds.

12.8.1.2.5. Criteria clause

This clause tells MATE whether to use the Pdu for analysis. It specifies a match AVPL, an AVPL match type (Strict, Every, or Loose) and the action to be performed (Accept or Reject) if the match succeeds. Once every attribute has been extracted and eventual transform list has been executed, and if the Criteria clause is present, the Pdu’s AVPL is matched against the match AVPL; if the match succeeds, the action specified is executed, i.e. the Pdu is accepted or rejected. The default behaviours used if the respective keywords are omitted are Strict and Accept. Accordingly, if the clause is omitted, all Pdus are accepted.

12.8.1.2.6. DropUnassigned clause

If set to TRUE, MATE will destroy the Pdu if it cannot assign it to a Gop. If set to FALSE (the default if not given), MATE will keep them.

12.8.1.2.7. DiscardPduData clause

If set to TRUE, MATE will delete the Pdu’s AVPL once it has analyzed it and eventually extracted some AVPs from it into the Gop’s AVPL. This is useful to save memory (of which MATE uses a lot). If set to FALSE (the default if not given), MATE will keep the Pdu attributes.

12.8.1.2.8. LastExtracted clause

If set to FALSE (the default if not given), MATE will continue to look for Pdus of other types in the frame. If set to TRUE, it will not try to create Pdus of other types from the current frame, yet it will continue to try for the current type.

12.8.1.3. Gop’s configuration actions

12.8.1.3.1. Gop declaration block header

Declares a Gop type and its prematch candidate key.

    Gop name On pduname Match key {
      Start match_avpl; // optional
      Stop match_avpl; // optional
      Extra match_avpl; // optional
      Transform transform_list; // optional
      Expiration time; // optional
      IdleTimeout time; // optional
      Lifetime time; // optional
      DropUnassigned [TRUE|FALSE]; //optional
      ShowTree [NoTree|PduTree|FrameTree|BasicTree]; //optional
      ShowTimes [TRUE|FALSE]; //optional, default TRUE
    };
12.8.1.3.2. Gop name

The name is a mandatory attribute of a Gop declaration. It is chosen arbitrarily, except that each name may only be used once in MATE’s configuration, regardless the class of an item it is used for. The name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as part of the filterable fields' names related to this type of Gop which MATE creates.

12.8.1.3.3. On clause

The name of Pdus which this type of Gop is supposed to be groupping. It is mandatory.

12.8.1.3.4. Match clause

Defines what AVPs form up the key part of the Gop’s AVPL (the Gop’s key AVPL or simply the Gop’s key). All Pdus matching the key AVPL of an active Gop are assigned to that Gop; a Pdu which contains the AVPs whose attribute names are listed in the Gop’s key AVPL, but they do not strictly match any active Gop’s key AVPL, will create a new Gop (unless a Start clause is given). When a Gop is created, the elements of its key AVPL are copied from the creating Pdu.

12.8.1.3.5. Start clause

If given, it tells MATE what match_avpl must a Pdu’s AVPL match, in addition to matching the Gop’s key, in order to start a Gop. If not given, any Pdu whose AVPL matches the Gop’s Key AVPL will act as a start for a Gop. The Pdu’s AVPs matching the match_avpl are not automatically copied into the Gop’s AVPL.

12.8.1.3.6. Stop clause

If given, it tells MATE what match_avpl must a Pdu’s AVPL match, in addition to matching the Gop’s key, in order to stop a Gop. If omitted, the Gop is "auto-stopped" - that is, the Gop is marked as stopped as soon as it is created. The Pdu’s AVPs matching the match_avpl are not automatically copied into the Gop’s AVPL.

12.8.1.3.7. Extra clause

If given, tells MATE which AVPs from the Pdu’s AVPL are to be copied into the Gop’s AVPL in addition to the Gop’s key.

12.8.1.3.8. Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Gop’s AVPL after the AVPs from each new Pdu, specified by the key AVPL and the Extra clause’s match_avpl, have been merged into it. The list is always executed completely, left to right. On the contrary, the list of Match clauses inside each individual Transform is executed only until the first match succeeds.

12.8.1.3.9. Expiration clause

A (floating) number of seconds after a Gop is Stop ped during which further Pdus matching the Stop ped Gop’s key but not the Start condition will still be assigned to that Gop. The default value of zero has an actual meaning of infinity, as it disables this timer, so all Pdus matching the Stop ped Gop’s key will be assigned to that Gop unless they match the Start condition.

12.8.1.3.10. IdleTimeout clause

A (floating) number of seconds elapsed from the last Pdu assigned to the Gop after which the Gop will be considered released. The default value of zero has an actual meaning of infinity, as it disables this timer, so the Gop won’t be released even if no Pdus arrive - unless the Lifetime timer expires.

12.8.1.3.11. Lifetime clause

A (floating) of seconds after the Gop Start after which the Gop will be considered released regardless anything else. The default value of zero has an actual meaning of infinity.

12.8.1.3.12. DropUnassigned clause

Whether or not a Gop that has not being assigned to any Gog should be discarded. If TRUE, the Gop is discarded right after creation. If FALSE, the default, the unassigned Gop is kept. Setting it to TRUE helps save memory and speed up filtering.

12.8.1.3.13. TreeMode clause

Controls the display of Pdus subtree of the Gop:

  • NoTree: completely suppresses showing the tree
  • PduTree: the tree is shown and shows the Pdus by Pdu Id
  • FrameTree: the tree is shown and shows the Pdus by the frame number in which they are
  • BasicTree: needs investigation
12.8.1.3.14. ShowTimes clause

Whether or not to show the times subtree of the Gop. If TRUE, the default, the subtree with the timers is added to the Gop’s tree. If FALSE, the subtree is suppressed.

12.8.1.4. Gog’s configuration actions

12.8.1.4.1. Gop declaration block header

Declares a Gog type and its prematch candidate key.

    Gog name {
      Member gopname (key); // mandatory, at least one
      Extra match_avpl; // optional
      Transform transform_list; // optional
      Expiration time; // optional, default 2.0
      GopTree [NoTree|PduTree|FrameTree|BasicTree]; // optional
      ShowTimes [TRUE|FALSE]; // optional, default TRUE
    };
12.8.1.4.2. Gop name

The name is a mandatory attribute of a Gog declaration. It is chosen arbitrarily, except that each name may only be used once in MATE’s configuration, regardless the class of an item it is used for. The name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as part of the filterable fields' names related to this type of Gop which MATE creates.

12.8.1.4.3. Member clause

Defines the key AVPL for the Gog individually for each Gop type gopname. All gopname type Gops whose key AVPL matches the corresponding key AVPL of an active Gog are assigned to that Gog; a Gop which contains the AVPs whose attribute names are listed in the Gog’s corresponding key AVPL, but they do not strictly match any active Gog’s key AVPL, will create a new Gog. When a Gog is created, the elements of its key AVPL are copied from the creating Gop.

Although the key AVPLs are specified separately for each of the Member gopname s, in most cases they are identical, as the very purpose of a Gog is to group together Gops made of Pdus of different types.

12.8.1.4.4. Extra clause

If given, tells MATE which AVPs from any of the Gop’s AVPL are to be copied into the Gog’s AVPL in addition to the Gog’s key.

12.8.1.4.5. Expiration clause

A (floating) number of seconds after all the Gops assigned to a Gog have been released during which new Gops matching any of the session keys should still be assigned to the existing Gog instead of creating a new one. Its value can range from 0.0 to infinite. Defaults to 2.0 seconds.

12.8.1.4.6. Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Gog’s AVPL after the AVPs from each new Gop, specified by the key AVPL and the Extra clause’s match_avpl, have been merged into it. The list is always executed completely, left to right. On the contrary, the list of Match clauses inside each individual Transform is executed only until the first match succeeds.

12.8.1.4.7. TreeMode clause

Controls the display of Gops subtree of the Gog:

  • NoTree: completely suppresses showing the tree
  • BasicTree: needs investigation
  • FullTree: needs investigation
12.8.1.4.8. ShowTimes clause

Whether or not to show the times subtree of the Gog. If TRUE, the default, the subtree with the timers is added to the Gog’s tree. If FALSE, the subtree is suppressed.

12.8.1.5. Settings Config AVPL

The Settings config element is used to pass to MATE various operational parameters. the possible parameters are

12.8.1.5.1. GogExpiration

How long in seconds after all the gops assigned to a gog have been released new gops matching any of the session keys should create a new gog instead of being assigned to the previous one. Its value can range from 0.0 to infinite. Defaults to 2.0 seconds.

12.8.1.5.2. DiscardPduData

Whether or not the AVPL of every Pdu should be deleted after it was being processed (saves memory). It can be either TRUE or FALSE. Defaults to TRUE. Setting it to FALSE can save you from a headache if your config does not work.

12.8.1.5.3. DiscardUnassignedPdu

Whether Pdus should be deleted if they are not assigned to any Gop. It can be either TRUE or FALSE. Defaults to FALSE. Set it to TRUE to save memory if unassigned Pdus are useless.

12.8.1.5.4. DiscardUnassignedGop

Whether GoPs should be deleted if they are not assigned to any session. It can be either TRUE or FALSE. Defaults to FALSE. Setting it to TRUE saves memory.

12.8.1.5.5. ShowPduTree
12.8.1.5.6. ShowGopTimes

12.8.1.6. Debugging Stuff

The following settings are used to debug MATE and its configuration. All levels are integers ranging from 0 (print only errors) to 9 (flood me with junk), defaulting to 0.

12.8.1.6.1. Debug declaration block header
    Debug {
      Filename "path/name"; //optional, no default value
      Level [0-9]; //optional, generic debug level
      Pdu Level [0-9]; //optional, specific debug level for Pdu handling
      Gop Level [0-9]; //optional, specific debug level for Gop handling
      Gog Level [0-9]; //optional, specific debug level for Gog handling
    };
12.8.1.6.2. Filename clause

The {{{path/name}}} is a full path to the file to which debug output is to be written. Non-existent file will be created, existing file will be overwritten at each opening of a capture file. If the statement is missing, debug messages are written to console, which means they are invisible on Windows.

12.8.1.6.3. Level clause

Sets the level of debugging for generic debug messages. It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).

12.8.1.6.4. Pdu Level clause

Sets the level of debugging for messages regarding Pdu creation. It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).

12.8.1.6.5. Gop Level clause

Sets the level of debugging for messages regarding Pdu analysis (that is how do they fit into ?GoPs). It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).

12.8.1.6.6. Gog Level clause

Sets the level of debugging for messages regarding GoP analysis (that is how do they fit into ?GoGs). It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).

12.8.1.6.7. Settings Example
Action=Settings; SessionExpiration=3.5; DiscardPduData=FALSE;

12.8.1.7. Action=Include

Will include a file to the configuration.

Action=Include; {Filename=filename;|Lib=libname;}
12.8.1.7.1. Filename

The filename of the file to include. If it does not beging with / it will look for the file in the current path.

12.8.1.7.2. Lib

The name of the lib config to include. will look for libname.mate in wiresharks_dir/matelib.

12.8.1.7.3. Include Example
Action=Include; Filename=rtsp.mate;

This will include the file called "rtsp.mate" into the current config.

Appendix A. Wireshark Messages

Wireshark provides you with additional information generated out of the plain packet data or it may need to indicate dissection problems. Messages generated by Wireshark are usually placed in square brackets (“[]”).

A.1. Packet List Messages

These messages might appear in the packet list.

A.1.1. [Malformed Packet]

Malformed packet means that the protocol dissector can’t dissect the contents of the packet any further. There can be various reasons:

  • Wrong dissector: Wireshark erroneously has chosen the wrong protocol dissector for this packet. This will happen e.g. if you are using a protocol not on its well known TCP or UDP port. You may try Analyze|Decode As to circumvent this problem.
  • Packet not reassembled: The packet is longer than a single frame and it is not reassembled, see Section 7.8, “Packet Reassembly” for further details.
  • Packet is malformed: The packet is actually wrong (malformed), meaning that a part of the packet is just not as expected (not following the protocol specifications).
  • Dissector is buggy: The corresponding protocol dissector is simply buggy or still incomplete.

Any of the above is possible. You’ll have to look into the specific situation to determine the reason. You could disable the dissector by disabling the protocol on the Analyze menu and check how Wireshark displays the packet then. You could (if it’s TCP) enable reassembly for TCP and the specific dissector (if possible) in the Edit|Preferences menu. You could check the packet contents yourself by reading the packet bytes and comparing it to the protocol specification. This could reveal a dissector bug. Or you could find out that the packet is indeed wrong.

A.1.2. [Packet size limited during capture]

The packet size was limited during capture, see “Limit each packet to n bytes” at the Section 4.5, “The “Capture Options” dialog box”. While dissecting, the current protocol dissector was simply running out of packet bytes and had to give up. There’s nothing else you can do now, except to repeat the whole capture process again with a higher (or no) packet size limitation.

A.2. Packet Details Messages

These messages might appear in the packet details.

A.2.1. [Response in frame: 123]

The current packet is the request of a detected request/response pair. You can directly jump to the corresponding response packet just by double clicking on this message.

A.2.2. [Request in frame: 123]

Same as “Response in frame: 123” above, but the other way round.

A.2.3. [Time from request: 0.123 seconds]

The time between the request and the response packets.

A.2.4. [Stream setup by PROTOCOL (frame 123)]

The session control protocol (SDP, H225, etc) message which signaled the creation of this session. You can directly jump to the corresponding packet just by double clicking on this message.

Appendix B. Files and Folders

B.1. Capture Files

To understand which information will remain available after the captured packets are saved to a capture file, it’s helpful to know a bit about the capture file contents.

Wireshark uses the pcapng file format as the default format to save captured packets. It is very flexible but other tools may not support it.

Wireshark also supports the libpcap file format. This is a much simpler format and is well established. However, it has some drawbacks: it’s not extensible and lacks some information that would be really helpful (e.g. being able to add a comment to a packet such as “the problems start here” would be really nice).

In addition to the libpcap format, Wireshark supports several different capture file formats. However, the problems described above also applies for these formats.

B.1.1. Libpcap File Contents

At the start of each libpcap capture file some basic information is stored like a magic number to identify the libpcap file format. The most interesting information of this file start is the link layer type (Ethernet, 802.11, MPLS, etc).

The following data is saved for each packet:

  • The timestamp with millisecond resolution
  • The packet length as it was “on the wire”
  • The packet length as it’s saved in the file
  • The packet’s raw bytes

A detailed description of the libpcap file format can be found at: https://wiki.wireshark.org/Development/LibpcapFileFormat

B.1.2. Not Saved in the Capture File

You should also know the things that are not saved in capture files:

  • Current selections (selected packet, …​)
  • Name resolution information. See Section 7.9, “Name Resolution” for details

    Pcapng files can optionally save name resolution information. Libpcap files can’t. Other file formats have varying levels of support.

  • The number of packets dropped while capturing
  • Packet marks set with “Edit/Mark Packet”
  • Time references set with “Edit/Time Reference”
  • The current display filter

B.2. Configuration File and Plugin Folders

To match the different policies for Unix-like systems and Windows, and different policies used on different Unix-like systems, the folders containing configuration files and plugins are different on different platforms. We indicate the location of the top-level folders under which configuration files and plugins are stored here, giving them placeholder names independent of their actual location, and use those names later when giving the location of the folders for configuration files and plugins.

[Tip] Tip

A list of the folders Wireshark actually uses can be found under the Folders tab in the dialog box shown when you select About Wireshark from the Help menu.

B.2.1. Folders on Windows

%APPDATA% is the personal application data folder, e.g.: C:\Users\username\AppData\Roaming\Wireshark (details can be found at: Section B.5.1, “Windows profiles”).

WIRESHARK is the Wireshark program folder, e.g.: C:\Program Files\Wireshark.

B.2.2. Folders on Unix-like systems

$XDG_CONFIG_HOME is the folder for user-specific configuration files. It’s usually $HOME/.config, where $HOME is the user’s home folder, which is usually something such as $HOME/username, or /Users/username on macOS.

If you are using macOS and you are running a copy of Wireshark installed as an application bundle, APPDIR is the top-level directory of the Wireshark application bundle, which will typically be /Applications/Wireshark.app. Otherwise, INSTALLDIR is the top-level directory under which reside the subdirectories in which components of Wireshark are installed. This will typically be /usr if Wireshark is bundled with the system (for example, provided as a package with a Linux distribution) and /usr/local if, for example, you’ve build Wireshark from source and installed it.

B.3. Configuration Files

Wireshark uses a number of configuration files while it is running. Some of these reside in the personal configuration folder and are used to maintain information between runs of Wireshark, while some of them are maintained in system areas.

The content format of the configuration files is the same on all platforms.

On Windows:

  • The personal configuration folder for Wireshark is the Wireshark sub-folder of that folder, i.e. %APPDATA%\Wireshark.
  • The global configuration folder for Wireshark is the Wireshark program folder and is also used as the system configuration folder.

On Unix-like systems:

  • The personal configuration folder is $XDG_CONFIG_HOME/wireshark. For backwards compatibility with Wireshark before 2.2, if $XDG_CONFIG_HOME/wireshark does not exist and $HOME/.wireshark is present, then the latter will be used.
  • If you are using macOS and you are running a copy of Wireshark installed as an application bundle, the global configuration folder is APPDIR/Contents/Resources/share/wireshark. Otherwise, the global configuration folder is INSTALLDIR/share/wireshark.
  • The /etc folder is the system configuration folder. The folder actually used on your system may vary, maybe something like: /usr/local/etc.

Table B.1. Configuration files overview

File/Folder Description

preferences

Settings from the Preferences dialog box.

recent

Recent GUI settings (e.g. recent files lists).

cfilters

Capture filters.

dfilters

Display filters.

colorfilters

Coloring rules.

disabled_protos

Disabled protocols.

ethers

Ethernet name resolution.

manuf

Ethernet name resolution.

hosts

IPv4 and IPv6 name resolution.

services

Network services.

subnets

IPv4 subnet name resolution.

ipxnets

IPX name resolution.

vlans

VLAN ID name resolution.

ss7pcs

SS7 point code resolution.


File contents
preferences

This file contains your Wireshark preferences, including defaults for capturing and displaying packets. It is a simple text file containing statements of the form:

variable: value

At program start, if there is a preferences file in the global configuration folder, it is read first. Then, if there is a preferences file in the personal configuration folder, that is read; if there is a preference set in both files, the setting in the personal preferences file overrides the setting in the global preference file.

If you press the Save button in the “Preferences” dialog box, all the current settings are written to the personal preferences file.

recent

This file contains various GUI related settings like the main window position and size, the recent files list and such. It is a simple text file containing statements of the form:

variable: value

It is read at program start and written at program exit.

cfilters

This file contains all the capture filters that you have defined and saved. It consists of one or more lines, where each line has the following format:

"<filter name>" <filter string>

At program start, if there is a cfilters file in the personal configuration folder, it is read. If there isn’t a cfilters file in the personal configuration folder, then, if there is a cfilters file in the global configuration folder, it is read.

When you press the Save button in the “Capture Filters” dialog box, all the current capture filters are written to the personal capture filters file.

dfilters

This file contains all the display filters that you have defined and saved. It consists of one or more lines, where each line has the following format:

"<filter name>" <filter string>

At program start, if there is a dfilters file in the personal configuration folder, it is read. If there isn’t a dfilters file in the personal configuration folder, then, if there is a dfilters file in the global configuration folder, it is read.

When you press the Save button in the “Display Filters” dialog box, all the current capture filters are written to the personal display filters file.

colorfilters

This file contains all the color filters that you have defined and saved. It consists of one or more lines, where each line has the following format:

@<filter name>@<filter string>@[<bg RGB(16-bit)>][<fg RGB(16-bit)>]

At program start, if there is a colorfilters file in the personal configuration folder, it is read. If there isn’t a colorfilters file in the personal configuration folder, then, if there is a colorfilters file in the global configuration folder, it is read.

Wwhen you press the Save button in the “Coloring Rules” dialog box, all the current color filters are written to the personal color filters file.

disabled_protos

Each line in this file specifies a disabled protocol name. The following are some examples:

tcp
udp

At program start, if there is a disabled_protos file in the global configuration folder, it is read first. Then, if there is a disabled_protos file in the personal configuration folder, that is read; if there is an entry for a protocol set in both files, the setting in the personal disabled protocols file overrides the setting in the global disabled protocols file.

When you press the Save button in the “Enabled Protocols” dialog box, the current set of disabled protocols is written to the personal disabled protocols file.

ethers

When Wireshark is trying to translate an hardware MAC address to a name, it consults the ethers file in the personal configuration folder first. If the address is not found in that file, Wireshark consults the ethers file in the system configuration folder.

Each line in these files consists of one hardware address and name separated by whitespace. The digits of hardware addresses are separated by colons (:), dashes (-) or periods(.). The following are some examples:

ff-ff-ff-ff-ff-ff    Broadcast
c0-00-ff-ff-ff-ff    TR_broadcast
00.2b.08.93.4b.a1    Freds_machine

The settings from this file are read in when a MAC address is to be translated to a name, and never written by Wireshark.

manuf

At program start, if there is a manuf file in the global configuration folder, it is read.

The entries in this file are used to translate the first three bytes of an Ethernet address into a manufacturers name. This file has the same format as the ethers file, except addresses are three bytes long.

An example is:

00:00:01    Xerox                  # XEROX CORPORATION

The settings from this file are read in at program start and never written by Wireshark.

hosts

Wireshark uses the entries in the hosts files to translate IPv4 and IPv6 addresses into names.

At program start, if there is a hosts file in the global configuration folder, it is read first. Then, if there is a hosts file in the personal configuration folder, that is read; if there is an entry for a given IP address in both files, the setting in the personal hosts file overrides the entry in the global hosts file.

This file has the same format as the usual /etc/hosts file on Unix systems.

An example is:

# Comments must be prepended by the # sign!
192.168.0.1 homeserver

The settings from this file are read in at program start and never written by Wireshark.

services

Wireshark uses the services files to translate port numbers into names.

At program start, if there is a services file in the global configuration folder, it is read first. Then, if there is a services file in the personal configuration folder, that is read; if there is an entry for a given port number in both files, the setting in the personal hosts file overrides the entry in the global hosts file.

An example is:

mydns       5045/udp     # My own Domain Name Server
mydns       5045/tcp     # My own Domain Name Server

The settings from these files are read in at program start and never written by Wireshark.

subnets

Wireshark uses the subnets files to translate an IPv4 address into a subnet name. If no exact match from a hosts file or from DNS is found, Wireshark will attempt a partial match for the subnet of the address.

At program start, if there is a subnets file in the personal configuration folder, it is read first. Then, if there is a subnets file in the global configuration folder, that is read; if there is a preference set in both files, the setting in the global preferences file overrides the setting in the personal preference file.

Each line in one of these files consists of an IPv4 address, a subnet mask length separated only by a “/” and a name separated by whitespace. While the address must be a full IPv4 address, any values beyond the mask length are subsequently ignored.

An example is:

# Comments must be prepended by the # sign!
192.168.0.0/24 ws_test_network

A partially matched name will be printed as “subnet-name.remaining-address”. For example, “192.168.0.1” under the subnet above would be printed as “ws_test_network.1”; if the mask length above had been 16 rather than 24, the printed address would be “ws_test_network.0.1”.

The settings from these files are read in at program start and never written by Wireshark.

ipxnets

When Wireshark is trying to translate an IPX network number to a name, it consults the ipxnets file in the personal configuration folder first. If the address is not found in that file, Wireshark consults the ipxnets file in the system configuration folder.

An example is:

C0.A8.2C.00      HR
c0-a8-1c-00      CEO
00:00:BE:EF      IT_Server1
110f             FileServer3

The settings from this file are read in when an IPX network number is to be translated to a name, and never written by Wireshark.

vlans

Wireshark uses the vlans file to translate VLAN tag IDs into names.

At program start, if there is a vlans file in the personal configuration folder, it is read.

Each line in this file consists of one VLAN tag ID and a describing name separated by whitespace or tab.

An example is:

123     Server-LAN
2049    HR-Client-LAN

The settings from this file are read in at program start and never written by Wireshark.

ss7pcs

Wireshark uses the ss7pcs file to translate SS7 point codes to node names.

At program start, if there is a ss7pcs file in the personal configuration folder, it is read.

Each line in this file consists of one network indicator followed by a dash followed by a point code in decimal and a node name separated by whitespace or tab.

An example is:

2-1234 MyPointCode1

The settings from this file are read in at program start and never written by Wireshark.

B.4. Plugin folders

Wireshark supports plugins for various purposes. Plugins can either be scripts written in Lua or code written in C or C++ and compiled to machine code.

Wireshark looks for plugins in both a personal plugin folder and a global plugin folder. Lua plugins are stored in the plugin folders; compiled plugins are stored in subfolders of the plugin folders, with the subfolder name being the Wireshark minor version number (X.Y). There is another hierarchical level for each Wireshark library (libwireshark, libwscodecs and libwiretap). So for example the location for a libwireshark plugin foo.so (foo.dll on Windows) would be PLUGINDIR/X.Y/epan (libwireshark used to be called libepan; the other folder names are codecs and wiretap).

On Windows:

  • The personal plugin folder is %APPDATA%\Wireshark\plugins.
  • The global plugin folder is WIRESHARK\plugins.

On Unix-like systems:

  • The personal plugin folder is ~/.local/lib/wireshark/plugins.
[Note] Note

To provide better support for binary plugins this folder changed in Wireshark 2.5. It is recommended to use the new folder but for lua scripts only you may continue to use $XDG_CONFIG_HOME/wireshark/plugins for backward-compatibility. This is useful to have older versions of Wireshark installed side-by-side. In case of duplicate file names between old and new the new folder wins.

  • If you are running on macOS and Wireshark is installed as an application bundle, the global plugin folder is %APPDIR%/Contents/PlugIns/wireshark, otherwise it’s INSTALLDIR/lib/wireshark/plugins.

B.5. Windows folders

Here you will find some details about the folders used in Wireshark on different Windows versions.

As already mentioned, you can find the currently used folders in the “About Wireshark” dialog.

B.5.1. Windows profiles

Windows uses some special directories to store user configuration files which define the “user profile”. This can be confusing, as the default directory location changed from Windows version to version and might also be different for English and internationalized versions of Windows.

[Note] Note

If you’ve upgraded to a new Windows version, your profile might be kept in the former location. The defaults mentioned here might not apply.

The following guides you to the right place where to look for Wireshark’s profile data.

Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, and associated server editions
C:\Users\username\AppData\Roaming\Wireshark.
Windows XP, Windows Server 2003, and Windows 2000 [1]
C:\Documents and Settings\username\Application Data. “Documents and Settings” and “Application Data” might be internationalized.
Windows NT 4 [1]
C:\WINNT\Profiles\username\Application Data\Wireshark
Windows ME, Windows 98 with user profiles [1]
In Windows ME and 98 you could enable separate user profiles. In that case, something like C:\windows\Profiles\username\Application Data\Wireshark is used.
Windows ME, Windows 98 without user profiles [1]
Without user profiles enabled the default location for all users was C:\windows\Application Data\Wireshark.

B.5.2. Windows roaming profiles

Some larger Windows environments use roaming profiles. If this is the case the configurations of all programs you use won’t be saved on your local hard drive. They will be stored on the domain server instead.

Your settings will travel with you from computer to computer with one exception. The “Local Settings” folder in your profile data (typically something like: C:\Documents and Settings\username\Local Settings) will not be transferred to the domain server. This is the default for temporary capture files.

B.5.3. Windows temporary folder

Wireshark uses the folder which is set by the TMPDIR or TEMP environment variable. This variable will be set by the Windows installer.

Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, and associated server editions
C:\Users\username\AppData\Local\Temp
Windows XP, Windows Server 2003, Windows 2000 [1]
C:\Documents and Settings\username\Local Settings\Temp
Windows NT [1]
C:\TEMP


[1] No longer supported by Wireshark. For historical reference only.

Appendix C. Protocols and Protocol Fields

Wireshark distinguishes between protocols (e.g. tcp) and protocol fields (e.g. tcp.port).

A comprehensive list of all protocols and protocol fields can be found in the “Display Filter Reference” at https://www.wireshark.org/docs/dfref/

Appendix D. Related command line tools

D.1. Introduction

Along with the main application, Wireshark comes with an array of command line tools which can be helpful for specialized tasks. Some of these tools will be described in this chapter. You can find more information about all of Wireshark’s command line tools on the web site.

D.2. tshark: Terminal-based Wireshark

TShark is a terminal oriented version of Wireshark designed for capturing and displaying packets when an interactive user interface isn’t necessary or available. It supports the same options as wireshark. For more information on tshark consult your local manual page (man tshark) or the online version.

Help information available from tshark

TShark (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Dump and analyze network traffic.
See https://www.wireshark.org for more information.

Usage: tshark [options] ...

Capture interface:
  -i <interface>           name or idx of interface (def: first non-loopback)
  -f <capture filter>      packet filter in libpcap filter syntax
  -s <snaplen>             packet snapshot length (def: appropriate maximum)
  -p                       don't capture in promiscuous mode
  -I                       capture in monitor mode, if available
  -B <buffer size>         size of kernel buffer (def: 2MB)
  -y <link type>           link layer type (def: first appropriate)
  --time-stamp-type <type> timestamp method for interface
  -D                       print list of interfaces and exit
  -L                       print list of link-layer types of iface and exit
  --list-time-stamp-types  print list of timestamp types for iface and exit

Capture stop conditions:
  -c <packet count>        stop after n packets (def: infinite)
  -a <autostop cond.> ...  duration:NUM - stop after NUM seconds
                           filesize:NUM - stop this file after NUM KB
                              files:NUM - stop after NUM files
Capture output:
  -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
                           interval:NUM - create time intervals of NUM secs
                           filesize:NUM - switch to next file after NUM KB
                              files:NUM - ringbuffer: replace after NUM files
Input file:
  -r <infile>              set the filename to read from (- to read from stdin)

Processing:
  -2                       perform a two-pass analysis
  -M <packet count>        perform session auto reset
  -R <read filter>         packet Read filter in Wireshark display filter syntax
                           (requires -2)
  -Y <display filter>      packet displaY filter in Wireshark display filter
                           syntax
  -n                       disable all name resolutions (def: all enabled)
  -N <name resolve flags>  enable specific name resolution(s): "mnNtdv"
  -d <layer_type>==<selector>,<decode_as_protocol> ...
                           "Decode As", see the man page for details
                           Example: tcp.port==8888,http
  -H <hosts file>          read a list of entries from a hosts file, which will
                           then be written to a capture file. (Implies -W n)
  --enable-protocol <proto_name>
                           enable dissection of proto_name
  --disable-protocol <proto_name>
                           disable dissection of proto_name
  --enable-heuristic <short_name>
                           enable dissection of heuristic protocol
  --disable-heuristic <short_name>
                           disable dissection of heuristic protocol
Output:
  -w <outfile|->           write packets to a pcap-format file named "outfile"
                           (or to the standard output for "-")
  -C <config profile>      start with specified configuration profile
  -F <output file type>    set the output file type, default is pcapng
                           an empty "-F" option will list the file types
  -V                       add output of packet tree        (Packet Details)
  -O <protocols>           Only show packet details of these protocols, comma
                           separated
  -P                       print packet summary even when writing to a file
  -S <separator>           the line separator to print between packets
  -x                       add output of hex and ASCII dump (Packet Bytes)
  -T pdml|ps|psml|json|jsonraw|ek|tabs|text|fields|?
                           format of text output (def: text)
  -j <protocolfilter>      protocols layers filter if -T ek|pdml|json selected
                           (e.g. "ip ip.flags text", filter does not expand child
                           nodes, unless child is specified also in the filter)
  -J <protocolfilter>      top level protocol filter if -T ek|pdml|json selected
                           (e.g. "http tcp", filter which expands all child nodes)
  -e <field>               field to print if -Tfields selected (e.g. tcp.port,
                           _ws.col.Info)
                           this option can be repeated to print multiple fields
  -E<fieldsoption>=<value> set options for output when -Tfields selected:
     bom=y|n               print a UTF-8 BOM
     header=y|n            switch headers on and off
     separator=/t|/s|<char> select tab, space, printable character as separator
     occurrence=f|l|a      print first, last or all occurrences of each field
     aggregator=,|/s|<char> select comma, space, printable character as
                           aggregator
     quote=d|s|n           select double, single, no quotes for values
  -t a|ad|d|dd|e|r|u|ud|?  output format of time stamps (def: r: rel. to first)
  -u s|hms                 output format of seconds (def: s: seconds)
  -l                       flush standard output after each packet
  -q                       be more quiet on stdout (e.g. when using statistics)
  -Q                       only log true errors to stderr (quieter than -q)
  -g                       enable group read access on the output file(s)
  -W n                     Save extra information in the file, if supported.
                           n = write network address resolution information
  -X <key>:<value>         eXtension options, see the man page for details
  -U tap_name              PDUs export mode, see the man page for details
  -z <statistics>          various statistics, see the man page for details
  --capture-comment <comment>
                           add a capture comment to the newly created
                           output file (only for pcapng)
  --export-objects <protocol>,<destdir> save exported objects for a protocol to
                           a directory named "destdir"
  --color                  color output text similarly to the Wireshark GUI,
                           requires a terminal with 24-bit color support
                           Also supplies color attributes to pdml and psml formats
                           (Note that attributes are nonstandard)
  --no-duplicate-keys      If -T json is specified, merge duplicate keys in an object
                           into a single key with as value a json array containing all
                           values
  --elastic-mapping-filter <protocols> If -G elastic-mapping is specified, put only the
                           specified protocols within the mapping file

Miscellaneous:
  -h                       display this help and exit
  -v                       display version info and exit
  -o <name>:<value> ...    override preference setting
  -K <keytab>              keytab file to use for kerberos decryption
  -G [report]              dump one of several available reports and exit
                           default report="fields"
                           use "-G help" for more help

Dumpcap can benefit from an enabled BPF JIT compiler if available.
You might want to enable it by executing:
 "echo 1 > /proc/sys/net/core/bpf_jit_enable"
Note that this can make your system less secure!

D.3. tcpdump: Capturing with “tcpdump” for viewing with Wireshark

It’s often more useful to capture packets using tcpdump rather than wireshark. For example, you might want to do a remote capture and either don’t have GUI access or don’t have Wireshark installed on the remote machine.

Older versions of tcpdump truncate packets to 68 or 96 bytes. If this is the case, use -s to capture full-sized packets:

$ tcpdump -i <interface> -s 65535 -w <some-file>

You will have to specify the correct interface and the name of a file to save into. In addition, you will have to terminate the capture with ^C when you believe you have captured enough packets.

tcpdump is not part of the Wireshark distribution. You can get it from http://www.tcpdump.org/ or as a standard package in most Linux distributions. For more information on tcpdump consult your local manual page (man tcpdump) or the online version.

D.4. dumpcap: Capturing with “dumpcap” for viewing with Wireshark

Dumpcap is a network traffic dump tool. It captures packet data from a live network and writes the packets to a file. Dumpcap’s native capture file format is pcapng, which is also the format used by Wireshark.

Without any options set it will use the pcap library to capture traffic from the first available network interface and write the received raw packet data, along with the packets’ time stamps into a pcapng file. The capture filter syntax follows the rules of the pcap library. For more information on dumpcap consult your local manual page (man dumpcap) or the online version.

Help information available from dumpcap

Dumpcap (Wireshark) 2.9.0 (v2.9.0rc0-2488-gfef9c0aa)
Capture network packets and dump them into a pcapng or pcap file.
See https://www.wireshark.org for more information.

Usage: dumpcap [options] ...

Capture interface:
  -i <interface>           name or idx of interface (def: first non-loopback),
                           or for remote capturing, use one of these formats:
                               rpcap://<host>/<interface>
                               [email protected]<host>:<port>
  -f <capture filter>      packet filter in libpcap filter syntax
  -s <snaplen>             packet snapshot length (def: appropriate maximum)
  -p                       don't capture in promiscuous mode
  -I                       capture in monitor mode, if available
  -B <buffer size>         size of kernel buffer in MiB (def: 2MiB)
  -y <link type>           link layer type (def: first appropriate)
  --time-stamp-type <type> timestamp method for interface
  -D                       print list of interfaces and exit
  -L                       print list of link-layer types of iface and exit
  --list-time-stamp-types  print list of timestamp types for iface and exit
  -d                       print generated BPF code for capture filter
  -k                       set channel on wifi interface:
                           <freq>,[<type>],[<center_freq1>],[<center_freq2>]
  -S                       print statistics for each interface once per second
  -M                       for -D, -L, and -S, produce machine-readable output

Stop conditions:
  -c <packet count>        stop after n packets (def: infinite)
  -a <autostop cond.> ...  duration:NUM - stop after NUM seconds
                           filesize:NUM - stop this file after NUM kB
                              files:NUM - stop after NUM files
                            packets:NUM - stop after NUM packets
Output (files):
  -w <filename>            name of file to save (def: tempfile)
  -g                       enable group read access on the output file(s)
  -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
                           interval:NUM - create time intervals of NUM secs
                           filesize:NUM - switch to next file after NUM kB
                              files:NUM - ringbuffer: replace after NUM files
                            packets:NUM - ringbuffer: replace after NUM packets
  -n                       use pcapng format instead of pcap (default)
  -P                       use libpcap format instead of pcapng
  --capture-comment <comment>
                           add a capture comment to the output file
                           (only for pcapng)

Miscellaneous:
  -N <packet_limit>        maximum number of packets buffered within dumpcap
  -C <byte_limit>          maximum number of bytes used for buffering packets
                           within dumpcap
  -t                       use a separate thread per interface
  -q                       don't report packet capture counts
  -v                       print version information and exit
  -h                       display this help and exit

Dumpcap can benefit from an enabled BPF JIT compiler if available.
You might want to enable it by executing:
 "echo 1 > /proc/sys/net/core/bpf_jit_enable"
Note that this can make your system less secure!

Example: dumpcap -i eth0 -a duration:60 -w output.pcapng
"Capture packets from interface eth0 until 60s passed into output.pcapng"

Use Ctrl-C to stop capturing at any time.

D.5. capinfos: Print information about capture files

capinfos can print information about capture files including the file type, number of packets, date and time information, and file hashes. Information can be printed in human and machine readable formats. For more information on capinfos consult your local manual page (man capinfos) or the online version.

Help information available from capinfos

Capinfos (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Print various information (infos) about capture files.
See https://www.wireshark.org for more information.

Usage: capinfos [options] <infile> ...

General infos:
  -t display the capture file type
  -E display the capture file encapsulation
  -I display the capture file interface information
  -F display additional capture file information
  -H display the SHA256, RMD160, and SHA1 hashes of the file
  -k display the capture comment

Size infos:
  -c display the number of packets
  -s display the size of the file (in bytes)
  -d display the total length of all packets (in bytes)
  -l display the packet size limit (snapshot length)

Time infos:
  -u display the capture duration (in seconds)
  -a display the capture start time
  -e display the capture end time
  -o display the capture file chronological status (True/False)
  -S display start and end times as seconds

Statistic infos:
  -y display average data rate (in bytes/sec)
  -i display average data rate (in bits/sec)
  -z display average packet size (in bytes)
  -x display average packet rate (in packets/sec)

Output format:
  -L generate long report (default)
  -T generate table report
  -M display machine-readable values in long reports

Table report options:
  -R generate header record (default)
  -r do not generate header record

  -B separate infos with TAB character (default)
  -m separate infos with comma (,) character
  -b separate infos with SPACE character

  -N do not quote infos (default)
  -q quote infos with single quotes (')
  -Q quote infos with double quotes (")

Miscellaneous:
  -h display this help and exit
  -C cancel processing if file open fails (default is to continue)
  -A generate all infos (default)
  -K disable displaying the capture comment

Options are processed from left to right order with later options superceding
or adding to earlier options.

If no options are given the default is to display all infos in long report
output format.

D.6. rawshark: Dump and analyze network traffic.

Rawshark reads a stream of packets from a file or pipe, and prints a line describing its output, followed by a set of matching fields for each packet on stdout. For more information on rawshark consult your local manual page (man rawshark) or the online version.

Help information available from rawshark

Rawshark (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Dump and analyze network traffic.
See https://www.wireshark.org for more information.

Usage: rawshark [options] ...

Input file:
  -r <infile>              set the pipe or file name to read from

Processing:
  -d <encap:linktype>|<proto:protoname>
                           packet encapsulation or protocol
  -F <field>               field to display
  -m                       virtual memory limit, in bytes
  -n                       disable all name resolution (def: all enabled)
  -N <name resolve flags>  enable specific name resolution(s): "mnNtdv"
  -p                       use the system's packet header format
                           (which may have 64-bit timestamps)
  -R <read filter>         packet filter in Wireshark display filter syntax
  -s                       skip PCAP header on input

Output:
  -l                       flush output after each packet
  -S                       format string for fields
                           (%D - name, %S - stringval, %N numval)
  -t ad|a|r|d|dd|e         output format of time stamps (def: r: rel. to first)

Miscellaneous:
  -h                       display this help and exit
  -o <name>:<value> ...    override preference setting
  -v                       display version info and exit

D.7. editcap: Edit capture files

editcap is a general-purpose utility for modifying capture files. Its main function is to remove packets from capture files, but it can also be used to convert capture files from one format to another, as well as to print information about capture files. For more information on editcap consult your local manual page (man editcap) or the online version.

Help information available from editcap. 

Editcap (Wireshark) 2.9.0 (v2.9.0rc0-1638-g57ee8486)
Edit and/or translate the format of capture files.
See https://www.wireshark.org for more information.

Usage: editcap [options] ... <infile> <outfile> [ <packet#>[-<packet#>] ... ]

<infile> and <outfile> must both be present.
A single packet or a range of packets can be selected.

Packet selection:
  -r                     keep the selected packets; default is to delete them.
  -A <start time>        only output packets whose timestamp is after (or equal
                         to) the given time (format as YYYY-MM-DD hh:mm:ss).
  -B <stop time>         only output packets whose timestamp is before the
                         given time (format as YYYY-MM-DD hh:mm:ss).

Duplicate packet removal:
  --novlan               remove vlan info from packets before checking for duplicates.
  -d                     remove packet if duplicate (window == 5).
  -D <dup window>        remove packet if duplicate; configurable <dup window>.
                         Valid <dup window> values are 0 to 1000000.
                         NOTE: A <dup window> of 0 with -v (verbose option) is
                         useful to print MD5 hashes.
  -w <dup time window>   remove packet if duplicate packet is found EQUAL TO OR
                         LESS THAN <dup time window> prior to current packet.
                         A <dup time window> is specified in relative seconds
                         (e.g. 0.000001).
           NOTE: The use of the 'Duplicate packet removal' options with
           other editcap options except -v may not always work as expected.
           Specifically the -r, -t or -S options will very likely NOT have the
           desired effect if combined with the -d, -D or -w.
  --skip-radiotap-header skip radiotap header when checking for packet duplicates.
                         Useful when processing packets captured by multiple radios
                         on the same channel in the vicinity of each other.

Packet manipulation:
  -s <snaplen>           truncate each packet to max. <snaplen> bytes of data.
  -C [offset:]<choplen>  chop each packet by <choplen> bytes. Positive values
                         chop at the packet beginning, negative values at the
                         packet end. If an optional offset precedes the length,
                         then the bytes chopped will be offset from that value.
                         Positive offsets are from the packet beginning,
                         negative offsets are from the packet end. You can use
                         this option more than once, allowing up to 2 chopping
                         regions within a packet provided that at least 1
                         choplen is positive and at least 1 is negative.
  -L                     adjust the frame (i.e. reported) length when chopping
                         and/or snapping.
  -t <time adjustment>   adjust the timestamp of each packet.
                         <time adjustment> is in relative seconds (e.g. -0.5).
  -S <strict adjustment> adjust timestamp of packets if necessary to ensure
                         strict chronological increasing order. The <strict
                         adjustment> is specified in relative seconds with
                         values of 0 or 0.000001 being the most reasonable.
                         A negative adjustment value will modify timestamps so
                         that each packet's delta time is the absolute value
                         of the adjustment specified. A value of -0 will set
                         all packets to the timestamp of the first packet.
  -E <error probability> set the probability (between 0.0 and 1.0 incl.) that
                         a particular packet byte will be randomly changed.
  -o <change offset>     When used in conjunction with -E, skip some bytes from the
                         beginning of the packet. This allows one to preserve some
                         bytes, in order to have some headers untouched.
  --seed <seed>          When used in conjunction with -E, set the seed to use for
                         the pseudo-random number generator. This allows one to
                         repeat a particular sequence of errors.
  -I <bytes to ignore>   ignore the specified number of bytes at the beginning
                         of the frame during MD5 hash calculation, unless the
                         frame is too short, then the full frame is used.
                         Useful to remove duplicated packets taken on
                         several routers (different mac addresses for
                         example).
                         e.g. -I 26 in case of Ether/IP will ignore
                         ether(14) and IP header(20 - 4(src ip) - 4(dst ip)).
  -a <framenum>:<comment> Add or replace comment for given frame number

Output File(s):
  -c <packets per file>  split the packet output to different files based on
                         uniform packet counts with a maximum of
                         <packets per file> each.
  -i <seconds per file>  split the packet output to different files based on
                         uniform time intervals with a maximum of
                         <seconds per file> each.
  -F <capture type>      set the output file type; default is pcapng. An empty
                         "-F" option will list the file types.
  -T <encap type>        set the output file encapsulation type; default is the
                         same as the input file. An empty "-T" option will
                         list the encapsulation types.

Miscellaneous:
  -h                     display this help and exit.
  -v                     verbose output.
                         If -v is used with any of the 'Duplicate Packet
                         Removal' options (-d, -D or -w) then Packet lengths
                         and MD5 hashes are printed to standard-error.

Capture file types available from editcap -F

editcap: The available capture file types for the "-F" flag are:
    5views - InfoVista 5View capture
    btsnoop - Symbian OS btsnoop
    commview - TamoSoft CommView
    dct2000 - Catapult DCT2000 trace (.out format)
    erf - Endace ERF capture
    eyesdn - EyeSDN USB S0/E1 ISDN trace format
    k12text - K12 text file
    lanalyzer - Novell LANalyzer
    logcat - Android Logcat Binary format
    logcat-brief - Android Logcat Brief text format
    logcat-long - Android Logcat Long text format
    logcat-process - Android Logcat Process text format
    logcat-tag - Android Logcat Tag text format
    logcat-thread - Android Logcat Thread text format
    logcat-threadtime - Android Logcat Threadtime text format
    logcat-time - Android Logcat Time text format
    modpcap - Modified tcpdump - pcap
    netmon1 - Microsoft NetMon 1.x
    netmon2 - Microsoft NetMon 2.x
    nettl - HP-UX nettl trace
    ngsniffer - Sniffer (DOS)
    ngwsniffer_1_1 - NetXray, Sniffer (Windows) 1.1
    ngwsniffer_2_0 - Sniffer (Windows) 2.00x
    niobserver - Network Instruments Observer
    nokiapcap - Nokia tcpdump - pcap
    nsecpcap - Wireshark/tcpdump/... - nanosecond pcap
    nstrace10 - NetScaler Trace (Version 1.0)
    nstrace20 - NetScaler Trace (Version 2.0)
    nstrace30 - NetScaler Trace (Version 3.0)
    nstrace35 - NetScaler Trace (Version 3.5)
    pcap - Wireshark/tcpdump/... - pcap
    pcapng - Wireshark/... - pcapng
    rf5 - Tektronix K12xx 32-bit .rf5 format
    rh6_1pcap - RedHat 6.1 tcpdump - pcap
    snoop - Sun snoop
    suse6_3pcap - SuSE 6.3 tcpdump - pcap
    visual - Visual Networks traffic capture

Encapsulation types available from editcap -T

editcap: The available encapsulation types for the "-T" flag are:
    ap1394 - Apple IP-over-IEEE 1394
    arcnet - ARCNET
    arcnet_linux - Linux ARCNET
    ascend - Lucent/Ascend access equipment
    atm-pdus - ATM PDUs
    atm-pdus-untruncated - ATM PDUs - untruncated
    atm-rfc1483 - RFC 1483 ATM
    ax25 - Amateur Radio AX.25
    ax25-kiss - AX.25 with KISS header
    bacnet-ms-tp - BACnet MS/TP
    bacnet-ms-tp-with-direction - BACnet MS/TP with Directional Info
    ber - ASN.1 Basic Encoding Rules
    bluetooth-bredr-bb-rf - Bluetooth BR/EDR Baseband RF
    bluetooth-h4 - Bluetooth H4
    bluetooth-h4-linux - Bluetooth H4 with linux header
    bluetooth-hci - Bluetooth without transport layer
    bluetooth-le-ll - Bluetooth Low Energy Link Layer
    bluetooth-le-ll-rf - Bluetooth Low Energy Link Layer RF
    bluetooth-linux-monitor - Bluetooth Linux Monitor
    can20b - Controller Area Network 2.0B
    chdlc - Cisco HDLC
    chdlc-with-direction - Cisco HDLC with Directional Info
    cosine - CoSine L2 debug log
    dbus - D-Bus
    dct2000 - Catapult DCT2000
    docsis - Data Over Cable Service Interface Specification
    docsis31_xra31 - DOCSIS with Excentis XRA pseudo-header
    dpauxmon - DisplayPort AUX channel with Unigraf pseudo-header
    dpnss_link - Digital Private Signalling System No 1 Link Layer
    dvbci - DVB-CI (Common Interface)
    enc - OpenBSD enc(4) encapsulating interface
    epon - Ethernet Passive Optical Network
    erf - Extensible Record Format
    ether - Ethernet
    ether-mpacket - IEEE 802.3br mPackets
    ether-nettl - Ethernet with nettl headers
    fc2 - Fibre Channel FC-2
    fc2sof - Fibre Channel FC-2 With Frame Delimiter
    fddi - FDDI
    fddi-nettl - FDDI with nettl headers
    fddi-swapped - FDDI with bit-swapped MAC addresses
    flexray - FlexRay
    frelay - Frame Relay
    frelay-with-direction - Frame Relay with Directional Info
    gcom-serial - GCOM Serial
    gcom-tie1 - GCOM TIE1
    gfp-f - ITU-T G.7041/Y.1303 Generic Framing Procedure Frame-mapped mode
    gfp-t - ITU-T G.7041/Y.1303 Generic Framing Procedure Transparent mode
    gprs-llc - GPRS LLC
    gsm_um - GSM Um Interface
    hhdlc - HiPath HDLC
    i2c - I2C
    ieee-802-11 - IEEE 802.11 Wireless LAN
    ieee-802-11-avs - IEEE 802.11 plus AVS radio header
    ieee-802-11-netmon - IEEE 802.11 plus Network Monitor radio header
    ieee-802-11-prism - IEEE 802.11 plus Prism II monitor mode radio header
    ieee-802-11-radio - IEEE 802.11 Wireless LAN with radio information
    ieee-802-11-radiotap - IEEE 802.11 plus radiotap radio header
    ieee-802-16-mac-cps - IEEE 802.16 MAC Common Part Sublayer
    infiniband - InfiniBand
    ios - Cisco IOS internal
    ip-ib - IP over IB
    ip-over-fc - RFC 2625 IP-over-Fibre Channel
    ip-over-ib - IP over Infiniband
    ipfix - IPFIX
    ipmb - Intelligent Platform Management Bus
    ipmi-trace - IPMI Trace Data Collection
    ipnet - Solaris IPNET
    irda - IrDA
    isdn - ISDN
    iso14443 - ISO 14443 contactless smartcard standards
    ixveriwave - IxVeriWave header and stats block
    jfif - JPEG/JFIF
    json - JavaScript Object Notation
    juniper-atm1 - Juniper ATM1
    juniper-atm2 - Juniper ATM2
    juniper-chdlc - Juniper C-HDLC
    juniper-ether - Juniper Ethernet
    juniper-frelay - Juniper Frame-Relay
    juniper-ggsn - Juniper GGSN
    juniper-mlfr - Juniper MLFR
    juniper-mlppp - Juniper MLPPP
    juniper-ppp - Juniper PPP
    juniper-pppoe - Juniper PPPoE
    juniper-st - Juniper Secure Tunnel Information
    juniper-svcs - Juniper Services
    juniper-vn - Juniper VN
    juniper-vp - Juniper Voice PIC
    k12 - K12 protocol analyzer
    lapb - LAPB
    lapd - LAPD
    layer1-event - EyeSDN Layer 1 event
    lin - Local Interconnect Network
    linux-atm-clip - Linux ATM CLIP
    linux-lapd - LAPD with Linux pseudo-header
    linux-sll - Linux cooked-mode capture
    logcat - Android Logcat Binary format
    logcat_brief - Android Logcat Brief text format
    logcat_long - Android Logcat Long text format
    logcat_process - Android Logcat Process text format
    logcat_tag - Android Logcat Tag text format
    logcat_thread - Android Logcat Thread text format
    logcat_threadtime - Android Logcat Threadtime text format
    logcat_time - Android Logcat Time text format
    loop - OpenBSD loopback
    loratap - LoRaTap
    ltalk - Localtalk
    message_analyzer_wfp_capture2_v4 - Message Analyzer WFP Capture2 v4
    message_analyzer_wfp_capture2_v6 - Message Analyzer WFP Capture2 v6
    message_analyzer_wfp_capture_auth_v4 - Message Analyzer WFP Capture Auth v4
    message_analyzer_wfp_capture_auth_v6 - Message Analyzer WFP Capture Auth v6
    message_analyzer_wfp_capture_v4 - Message Analyzer WFP Capture v4
    message_analyzer_wfp_capture_v6 - Message Analyzer WFP Capture v6
    mime - MIME
    most - Media Oriented Systems Transport
    mp2ts - ISO/IEC 13818-1 MPEG2-TS
    mpeg - MPEG
    mtp2 - SS7 MTP2
    mtp2-with-phdr - MTP2 with pseudoheader
    mtp3 - SS7 MTP3
    mux27010 - MUX27010
    netanalyzer - netANALYZER
    netanalyzer-transparent - netANALYZER-Transparent
    netlink - Linux Netlink
    netmon_event - Network Monitor Network Event
    netmon_filter - Network Monitor Filter
    netmon_header - Network Monitor Header
    netmon_network_info - Network Monitor Network Info
    nfc-llcp - NFC LLCP
    nflog - NFLOG
    nordic_ble - Nordic BLE Sniffer
    nstrace10 - NetScaler Encapsulation 1.0 of Ethernet
    nstrace20 - NetScaler Encapsulation 2.0 of Ethernet
    nstrace30 - NetScaler Encapsulation 3.0 of Ethernet
    nstrace35 - NetScaler Encapsulation 3.5 of Ethernet
    null - NULL/Loopback
    packetlogger - PacketLogger
    pflog - OpenBSD PF Firewall logs
    pflog-old - OpenBSD PF Firewall logs, pre-3.4
    pktap - Apple PKTAP
    ppi - Per-Packet Information header
    ppp - PPP
    ppp-with-direction - PPP with Directional Info
    pppoes - PPP-over-Ethernet session
    raw-icmp-nettl - Raw ICMP with nettl headers
    raw-icmpv6-nettl - Raw ICMPv6 with nettl headers
    raw-telnet-nettl - Raw telnet with nettl headers
    rawip - Raw IP
    rawip-nettl - Raw IP with nettl headers
    rawip4 - Raw IPv4
    rawip6 - Raw IPv6
    redback - Redback SmartEdge
    rfc7468 - RFC 7468 file
    rtac-serial - RTAC serial-line
    ruby_marshal - Ruby marshal object
    s4607 - STANAG 4607
    s5066-dpdu - STANAG 5066 Data Transfer Sublayer PDUs(D_PDU)
    sccp - SS7 SCCP
    sctp - SCTP
    sdh - SDH
    sdjournal - systemd journal
    sdlc - SDLC
    sita-wan - SITA WAN packets
    slip - SLIP
    socketcan - SocketCAN
    symantec - Symantec Enterprise Firewall
    tnef - Transport-Neutral Encapsulation Format
    tr - Token Ring
    tr-nettl - Token Ring with nettl headers
    tzsp - Tazmen sniffer protocol
    unknown - Unknown
    unknown-nettl - Unknown link-layer type with nettl headers
    usb-darwin - USB packets with Darwin (macOS, etc.) headers
    usb-freebsd - USB packets with FreeBSD header
    usb-linux - USB packets with Linux header
    usb-linux-mmap - USB packets with Linux header and padding
    usb-usbpcap - USB packets with USBPcap header
    user0 - USER 0
    user1 - USER 1
    user2 - USER 2
    user3 - USER 3
    user4 - USER 4
    user5 - USER 5
    user6 - USER 6
    user7 - USER 7
    user8 - USER 8
    user9 - USER 9
    user10 - USER 10
    user11 - USER 11
    user12 - USER 12
    user13 - USER 13
    user14 - USER 14
    user15 - USER 15
    v5-ef - V5 Envelope Function
    vsock - Linux vsock
    whdlc - Wellfleet HDLC
    wireshark-upper-pdu - Wireshark Upper PDU export
    wpan - IEEE 802.15.4 Wireless PAN
    wpan-nofcs - IEEE 802.15.4 Wireless PAN with FCS not present
    wpan-nonask-phy - IEEE 802.15.4 Wireless PAN non-ASK PHY
    x2e-serial - X2E serial line capture
    x2e-xoraya - X2E Xoraya
    x25-nettl - X.25 with nettl headers
    xeth - Xerox 3MB Ethernet

D.8. mergecap: Merging multiple capture files into one

Mergecap is a program that combines multiple saved capture files into a single output file specified by the -w argument. Mergecap knows how to read libpcap capture files, including those of tcpdump. In addition, Mergecap can read capture files from snoop (including Shomiti) and atmsnoop, LanAlyzer, Sniffer (compressed or uncompressed), Microsoft Network Monitor, AIX’s iptrace, NetXray, Sniffer Pro, RADCOM’s WAN/LAN analyzer, Lucent/Ascend router debug output, HP-UX’s nettl, and the dump output from Toshiba’s ISDN routers. There is no need to tell Mergecap what type of file you are reading; it will determine the file type by itself. Mergecap is also capable of reading any of these file formats if they are compressed using gzip. Mergecap recognizes this directly from the file; the “.gz” extension is not required for this purpose.

By default, it writes the capture file in pcapng format, and writes all of the packets in the input capture files to the output file. The -F flag can be used to specify the format in which to write the capture file; it can write the file in libpcap format (standard libpcap format, a modified format used by some patched versions of libpcap, the format used by Red Hat Linux 6.1, or the format used by SuSE Linux 6.3), snoop format, uncompressed Sniffer format, Microsoft Network Monitor 1.x format, and the format used by Windows-based versions of the Sniffer software.

Packets from the input files are merged in chronological order based on each frame’s timestamp, unless the -a flag is specified. Mergecap assumes that frames within a single capture file are already stored in chronological order. When the -a flag is specified, packets are copied directly from each input file to the output file, independent of each frame’s timestamp.

If the -s flag is used to specify a snapshot length, frames in the input file with more captured data than the specified snapshot length will have only the amount of data specified by the snapshot length written to the output file. This may be useful if the program that is to read the output file cannot handle packets larger than a certain size (for example, the versions of snoop in Solaris 2.5.1 and Solaris 2.6 appear to reject Ethernet frames larger than the standard Ethernet MTU, making them incapable of handling gigabit Ethernet captures if jumbo frames were used).

If the -T flag is used to specify an encapsulation type, the encapsulation type of the output capture file will be forced to the specified type, rather than being the type appropriate to the encapsulation type of the input capture file. Note that this merely forces the encapsulation type of the output file to be the specified type; the packet headers of the packets will not be translated from the encapsulation type of the input capture file to the specified encapsulation type (for example, it will not translate an Ethernet capture to an FDDI capture if an Ethernet capture is read and -T fddi is specified).

For more information on mergecap consult your local manual page (man mergecap) or the online version.

Help information available from mergecap

Mergecap (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Merge two or more capture files into one.
See https://www.wireshark.org for more information.

Usage: mergecap [options] -w <outfile>|- <infile> [<infile> ...]

Output:
  -a                concatenate rather than merge files.
                    default is to merge based on frame timestamps.
  -s <snaplen>      truncate packets to <snaplen> bytes of data.
  -w <outfile>|-    set the output filename to <outfile> or '-' for stdout.
  -F <capture type> set the output file type; default is pcapng.
                    an empty "-F" option will list the file types.
  -I <IDB merge mode> set the merge mode for Interface Description Blocks; default is 'all'.
                    an empty "-I" option will list the merge modes.

Miscellaneous:
  -h                display this help and exit.
  -v                verbose output.

A simple example merging dhcp-capture.pcapng and imap-1.pcapng into outfile.pcapng is shown below.

Simple example of using mergecap. 

$ mergecap -w outfile.pcapng dhcp-capture.pcapng imap-1.pcapng

D.9. text2pcap: Converting ASCII hexdumps to network captures

There may be some occasions when you wish to convert a hex dump of some network traffic into a libpcap file.

text2pcap is a program that reads in an ASCII hex dump and writes the data described into a libpcap-style capture file. text2pcap can read hexdumps with multiple packets in them, and build a capture file of multiple packets. text2pcap is also capable of generating dummy Ethernet, IP and UDP headers, in order to build fully processable packet dumps from hexdumps of application-level data only.

text2pcap understands a hexdump of the form generated by od -A x -t x1. In other words, each byte is individually displayed and surrounded with a space. Each line begins with an offset describing the position in the file. The offset is a hex number (can also be octal - see -o), of more than two hex digits. Here is a sample dump that text2pcap can recognize:

000000 00 e0 1e a7 05 6f 00 10 ........
000008 5a a0 b9 12 08 00 46 00 ........
000010 03 68 00 00 00 00 0a 2e ........
000018 ee 33 0f 19 08 7f 0f 19 ........
000020 03 80 94 04 00 00 10 01 ........
000028 16 a2 0a 00 03 50 00 0c ........
000030 01 01 0f 19 03 80 11 01 ........

There is no limit on the width or number of bytes per line. Also the text dump at the end of the line is ignored. Bytes/hex numbers can be uppercase or lowercase. Any text before the offset is ignored, including email forwarding characters “>”. Any lines of text between the bytestring lines is ignored. The offsets are used to track the bytes, so offsets must be correct. Any line which has only bytes without a leading offset is ignored. An offset is recognized as being a hex number longer than two characters. Any text after the bytes is ignored (e.g. the character dump). Any hex numbers in this text are also ignored. An offset of zero is indicative of starting a new packet, so a single text file with a series of hexdumps can be converted into a packet capture with multiple packets. Multiple packets are read in with timestamps differing by one second each. In general, short of these restrictions, text2pcap is pretty liberal about reading in hexdumps and has been tested with a variety of mangled outputs (including being forwarded through email multiple times, with limited line wrap etc.)

There are a couple of other special features to note. Any line where the first non-whitespace character is “#” will be ignored as a comment. Any line beginning with #TEXT2PCAP is a directive and options can be inserted after this command to be processed by text2pcap. Currently there are no directives implemented; in the future, these may be used to give more fine grained control on the dump and the way it should be processed e.g. timestamps, encapsulation type etc.

text2pcap also allows the user to read in dumps of application-level data, by inserting dummy L2, L3 and L4 headers before each packet. Possibilities include inserting headers such as Ethernet, Ethernet + IP, Ethernet + IP + UDP, or Ethernet + Ip + TCP before each packet. This allows Wireshark or any other full-packet decoder to handle these dumps.

For more information on text2pcap consult your local manual page (man text2pcap) or the online version.

Help information available from text2pcap. 

Text2pcap (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Generate a capture file from an ASCII hexdump of packets.
See https://www.wireshark.org for more information.

Usage: text2pcap [options] <infile> <outfile>

where  <infile> specifies input  filename (use - for standard input)
      <outfile> specifies output filename (use - for standard output)

Input:
  -o hex|oct|dec         parse offsets as (h)ex, (o)ctal or (d)ecimal;
                         default is hex.
  -t <timefmt>           treat the text before the packet as a date/time code;
                         the specified argument is a format string of the sort
                         supported by strptime.
                         Example: The time "10:15:14.5476" has the format code
                         "%H:%M:%S."
                         NOTE: The subsecond component delimiter, '.', must be
                         given, but no pattern is required; the remaining
                         number is assumed to be fractions of a second.
                         NOTE: Date/time fields from the current date/time are
                         used as the default for unspecified fields.
  -D                     the text before the packet starts with an I or an O,
                         indicating that the packet is inbound or outbound.
                         This is only stored if the output format is pcapng.
  -a                     enable ASCII text dump identification.
                         The start of the ASCII text dump can be identified
                         and excluded from the packet data, even if it looks
                         like a HEX dump.
                         NOTE: Do not enable it if the input file does not
                         contain the ASCII text dump.

Output:
  -l <typenum>           link-layer type number; default is 1 (Ethernet).  See
                         http://www.tcpdump.org/linktypes.html for a list of
                         numbers.  Use this option if your dump is a complete
                         hex dump of an encapsulated packet and you wish to
                         specify the exact type of encapsulation.
                         Example: -l 7 for ARCNet packets.
  -m <max-packet>        max packet length in output; default is 262144

Prepend dummy header:
  -e <l3pid>             prepend dummy Ethernet II header with specified L3PID
                         (in HEX).
                         Example: -e 0x806 to specify an ARP packet.
  -i <proto>             prepend dummy IP header with specified IP protocol
                         (in DECIMAL).
                         Automatically prepends Ethernet header as well.
                         Example: -i 46
  -4 <srcip>,<destip>    prepend dummy IPv4 header with specified
                         dest and source address.
                         Example: -4 10.0.0.1,10.0.0.2
  -6 <srcip>,<destip>    replace IPv6 header with specified
                         dest and source address.
                         Example: -6 fe80:0:0:0:202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334
  -u <srcp>,<destp>      prepend dummy UDP header with specified
                         source and destination ports (in DECIMAL).
                         Automatically prepends Ethernet & IP headers as well.
                         Example: -u 1000,69 to make the packets look like
                         TFTP/UDP packets.
  -T <srcp>,<destp>      prepend dummy TCP header with specified
                         source and destination ports (in DECIMAL).
                         Automatically prepends Ethernet & IP headers as well.
                         Example: -T 50,60
  -s <srcp>,<dstp>,<tag> prepend dummy SCTP header with specified
                         source/dest ports and verification tag (in DECIMAL).
                         Automatically prepends Ethernet & IP headers as well.
                         Example: -s 30,40,34
  -S <srcp>,<dstp>,<ppi> prepend dummy SCTP header with specified
                         source/dest ports and verification tag 0.
                         Automatically prepends a dummy SCTP DATA
                         chunk header with payload protocol identifier ppi.
                         Example: -S 30,40,34

Miscellaneous:
  -h                     display this help and exit.
  -d                     show detailed debug of parser states.
  -q                     generate no output at all (automatically disables -d).
  -n                     use pcapng instead of pcap as output format.

D.10. reordercap: Reorder a capture file

reordercap lets you reorder a capture file according to the packets timestamp. For more information on reordercap consult your local manual page (man reordercap) or the online version.

Help information available from reordercap. 

Reordercap (Wireshark) 2.9.0 (v2.9.0rc0-1249-ga108e49d)
Reorder timestamps of input file frames into output file.
See https://www.wireshark.org for more information.

Usage: reordercap [options] <infile> <outfile>

Options:
  -n        don't write to output file if the input file is ordered.
  -h        display this help and exit.

Chapter 13. This Document’s License (GPL)

As with the original license and documentation distributed with Wireshark, this document is covered by the GNU General Public License (GNU GPL).

If you haven’t read the GPL before, please do so. It explains all the things that you are allowed to do with this code and documentation.

		    GNU GENERAL PUBLIC LICENSE
		       Version 2, June 1991

 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

			    Preamble

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License is intended to guarantee your freedom to share and change free
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Foundation's software and to any other program whose authors commit to
using it.  (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.)  You can apply it to
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  When we speak of free software, we are referring to freedom, not
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  To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
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  For example, if you distribute copies of such a program, whether
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    allowed only for noncommercial distribution and only if you
    received the program in object code or executable form with such
    an offer, in accord with Subsection b above.)

The source code for a work means the preferred form of the work for
making modifications to it.  For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable.  However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.

If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.

  4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.

  5. You are not required to accept this License, since you have not
signed it.  However, nothing else grants you permission to modify or
distribute the Program or its derivative works.  These actions are
prohibited by law if you do not accept this License.  Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.

  6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions.  You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.

  7. If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all.  For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.

It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices.  Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.

  8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded.  In such case, this License incorporates
the limitation as if written in the body of this License.

  9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

Each version is given a distinguishing version number.  If the Program
specifies a version number of this License which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation.  If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.

  10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission.  For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this.  Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.

			    NO WARRANTY

  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.

		     END OF TERMS AND CONDITIONS

	    How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA


Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

    Gnomovision version 69, Copyright (C) year  name of author
    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary.  Here is a sample; alter the names:

  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
  `Gnomovision' (which makes passes at compilers) written by James Hacker.

  <signature of Ty Coon>, 1 April 1989
  Ty Coon, President of Vice

This General Public License does not permit incorporating your program into
proprietary programs.  If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library.  If this is what you want to do, use the GNU Library General
Public License instead of this License.