Bit-Twist

Supported systems: Windows, Linux, BSD, and macOS.

Bit-Twist is a simple yet powerful libpcap-based Ethernet packet generator and packet editor. It is designed to complement tcpdump, which by itself has done a great job at capturing network traffic.

With Bit-Twist, you can now regenerate your captured traffic onto a live network! Packets are generated from tcpdump trace file (.pcap file). Bit-Twist comes with a comprehensive trace file editor to allow you to change the contents of a trace file. Bit-Twist is designed for exceptional speed, allowing you to edit 10 million packets in under 3 seconds and send them over a live network at throughput levels that match your NIC's maximum line rate, up to 10 Gbps.

Bit-Twist is ideal for simulating network traffic and scenarios, testing firewalls, IDS, IPS, routers, switches, load balancers, and other network equipment, as well as troubleshooting various network issues.

Preview

This session demonstrates the use of Bit-Twist to create a .pcap file and to send its packets onto a live network.

Features

These are just a few significant features that makes Bit-Twist unique and stands out as one of the best Ethernet packet generator and packet editor package made available to the open source community.

Highly portable: Bit-Twist runs on Windows, Linux, BSD, and macOS.
Send multiple trace files indefinitely with set interval, packets per second, or line rate between 1 Mbps to 10 Gbps using built-in token bucket algorithm.
Comprehensive trace file editor to edit most fields in Ethernet, VLAN, ARP, IPv4, IPv6, ICMPv4, ICMPv6, TCP, and UDP headers. Templates are also included to generate packets with these headers without needing an existing trace file.
Automatic header checksum correction (with option to disable).
Send packets with custom QoS bits to test classification and queuing features of switches and routers.
Send packets with uniformly distributed random numbers for IP addresses, port numbers, TCP sequence numbers, etc.
Append custom payload (e.g. copy of hex stream from Wireshark) to existing packets after a specific header, handy for testing new protocols.
Send packets with truncated or expanded length in bytes, facilitating incremental throughput testing.
Highly scriptable: With proper manipulation, you can turn Bit-Twist into a versatile packet generator and packet editor tooling to meet your network testing requirements.

For the complete feature list, see Bit-Twist man pages:

bittwist.1 - pcap based ethernet packet generator
bittwiste.1 - pcap capture file editor

Downloads

Latest release version is Bit-Twist 4.7, released on November 1, 2024. For installation, please follow the instructions in the README.md included in the package.

bittwist-windows-4.7.zip (executable files included) SHA256=500ccc65e391223412b95d76a862ed5e6978bc7d5616340f2207f0c031266fb2 Npcap installation is required as prerequisite for Windows.

bittwist-linux-4.7.tar.gz (executable files for x86_64 and aarch64 included) SHA256=4c79b6ef20b1ddfac583654ee5ed7567e9972bd75c3c4828802e116ae945819c

bittwist-bsd-4.7.tar.gz SHA256=801aa4f842f0eeed667a435f81c839c40bcfe6e4abf548ef7ec24890c73df542

bittwist-macos-4.7.tar.gz SHA256=2ff00070d57221672af5198268088ffee8ed6b5ade33d6f26be5b3b4125b48f1

You may also download Bit-Twist from SourceForge.net File Releases for Bit-Twist. Older releases are available here for regression testing.

License

SPDX-License-Identifier: GPL-2.0-or-later

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.

Contact

Please do not hesitate to reach out to me at ayeowch@gmail.com for any inquiries or bug reports.

Prior to submitting your bug report, kindly ensure that you are using the latest version. For more information on known bugs, please refer to the BUGS section in the Bit-Twist manual pages.

If you are interested in leveraging Bit-Twist for your business needs, feel free to discuss commercial licensing options with me via email.

Maintainer

Bit-Twist project is maintained and developed by Addy Yeow.