Tcpreplay - Pcap Editing And Replay Tools For *NIX And Windows

Tcpreplay is a suite of GPLv3 licensed utilities for UNIX (and Win32 under Cygwin) operating systems for editing and replaying network traffic which was previously captured by tools like tcpdump and Ethereal/Wireshark. It allows you to classify traffic as client or server, rewrite Layer 2, 3 and 4 packets and finally replay the traffic back onto the network and through other devices such as switches, routers, firewalls, NIDS and IPS's. Tcpreplay supports both single and dual NIC modes for testing both sniffing and in-line devices.
Tcpreplay is used by numerous firewall, IDS, IPS, NetFlow and other networking vendors, enterprises, universities, labs and open source projects. If your organization uses Tcpreplay, please let us know who you are and what you use it for so that I can continue to add features which are useful.
Tcpreplay is designed to work with network hardware and normally does not penetrate deeper than Layer 2. Yazan Siam with sponsorship from Cisco developed tcpliveplay to replay TCP pcap files directly to servers. Use this utility if you want to test the entire network stack and into the application.
As of version 4.0, Tcpreplay has been enhanced to address the complexities of testing and tuning IP Flow/NetFlow hardware. Enhancements include:
  • Support for netmap modified network drivers for 10GigE wire-speed performance
  • Increased accuracy for playback speed
  • Increased accuracy of results reporting
  • Flow statistics including Flows Per Second (fps)
  • Flow analysis for analysis and fine tuning of flow expiry timeouts
  • Hundreds of thousands of flows per second (dependent flow sizes in pcap file)

Version 4.0 is the first version delivered by Fred Klassen and sponsored by AppNeta. Many thanks to the author of Tcpreplay, Aaron Turner who has supplied the world with a a solid and full-featured test product thus far. The new author strives to take Tcprelay performance to levels normally only seen in commercial network test equipment.

The Tcpreplay suite includes the following tools:

Network playback products:
  • tcpreplay - replays pcap files at arbitrary speeds onto the network with an option to replay with random IP addresses
  • tcpreplay-edit - replays pcap files at arbitrary speeds onto the network with numerous options to modify packets packets on the fly
  • tcpliveplay - replays TCP network traffic stored in a pcap file on live networks in a manner that a remote server will respond to

Pcap file editors and utilities:
  • tcpprep - multi-pass pcap file pre-processor which determines packets as client or server and splits them into creates output files for use by tcpreplay and tcprewrite
  • tcprewrite - pcap file editor which rewrites TCP/IP and Layer 2 packet headers
  • tcpbridge - bridge two network segments with the power of tcprewrite
  • tcpcapinfo - raw pcap file decoder and debugger

Install package
Please visit our downloads page on our wiki for detailed download and installation instructions.

Simple directions for Unix users:
sudo make install

Build netmap feature
This feature will detect netmap capable network drivers on Linux and BSD systems. If detected, the network driver is bypassed for the execution duration of tcpreplay and tcpreplay-edit, and network buffers will be written to directly. This will allow you to achieve full line rates on commodity network adapters, similar to rates achieved by commercial network traffic generators.
Note that bypassing the network driver will disrupt other applications connected through the test interface. Don't test on the same interface you ssh'ed into.
Download latest and install netmap from If you extracted netmap into /usr/src/ or /usr/local/src you can build normally. Otherwise you will have to specify the netmap source directory, for example:
./configure --with-netmap=/home/fklassen/git/netmap
sudo make install
You can also find netmap source here.
Detailed installation instructions are available in the INSTALL document in the tar ball.

Install Tcpreplay from source code
Download the tar ball or zip file. Optionally clone the git repository:
git clone [email protected]:appneta/tcpreplay.git

If you have a question or think you are experiencing a bug, submit them here. It is important that you provide enough information for us to help you.
If your problem has to do with COMPILING tcpreplay:
  • Version of tcpreplay you are trying to compile
  • Platform (Red Hat Linux 9 on x86, Solaris 7 on SPARC, OS X on PPC, etc)
  • Contents of config.status
  • Output from configure and make
  • Any additional information you think that would be useful.
If your problem has to do with RUNNING tcpreplay or one of the sub-tools:
  • Version information (output of -V)
  • Command line used (options and arguments)
  • Platform (Red Hat Linux 9 on Intel, Solaris 7 on SPARC, etc)
  • Make & model of the network card(s) and driver(s) version
  • Error message (if available) and/or description of problem
  • If possible, attach the pcap file used (compressed with bzip2 or gzip preferred)
  • The core dump or backtrace if available
  • Detailed description of your problem or what you are trying to accomplish
Note: The author of tcpreplay primarily uses OS X and Linux; hence, if you're reporting an issue on another platform, it is important that you give very detailed information as I may not be able to reproduce your issue.
You are also strongly encouraged to read the extensive documentation (man pages, FAQ, documents in /docs and email list archives) BEFORE posting to the tcpreplay-users email list:
If you have a bug to report you can submit it here:
If you want to help with development, visit our developers wiki:
Lastly, please don't email the authors directly with your questions. Doing so prevents others from potentially helping you and your question/answer from showing up in the list archives.

Authors and Contributors
Tcpreplay is authored by Aaron Turner. In 2013 Fred Klassen, Founder and VP Network Technology, AppNeta added performance features and enhancements, and ultimately took over the maintenance of Tcpreplay.
The source code repository has moved to GitHub. You can get a working copy of the repository by installing git and executing:
git clone

How To Contribute
It's easy. Basically you...

You will find that you will not be able to contribute to the Tcpreplay project directly if you use clone the appneta/tcpreplay repo. If you believe that you may someday contribute to the repository, GitHub provides an innovative approach. Forking the @appneta/tcpreplay repository allows you to work on your own copy of the repository and submit code changes without first asking permission from the authors. Forking is also considered to be a compliment so fork away:
  • if you haven't already done so, get yourself a free GitHub ID and visit @appneta/tcpreplay
  • click the Fork button to get your own private copy of the repository
  • on your build system clone your private repository:
git clone [email protected]:<your ID>/tcpreplay.git
  • we like to keep the master branch available for projection ready code so we recommend that you make a branch for each feature or bug fix
  • when you are happy with your work, push it to your GitHub repository
  • on your GitHub repository select your new branch and submit a Pull Request to master
  • optionally monitor the status of your submission here
We will review and possibly discuss the changes with you through GitHub services. If we accept the submission, it will instantly be applied to the production master branch.

Additional Information
Please visit our wiki.
or visit our developers wiki

Tcpreplay - Pcap Editing And Replay Tools For *NIX And Windows Tcpreplay - Pcap Editing And Replay Tools For *NIX And Windows Reviewed by Zion3R on 9:32 AM Rating: 5