Wikipedia
Packetsquare
PacketSquare (CapEdit) is a free and open-source pcap-based network protocol testing tool. It is used for testing network devices ( IDS/IPS, firewall, routers switches etc.,), network troubleshooting, analysis, software and communications protocol development, and education.
Currently PacketSquare-CapEdit runs on Linux, using the GTK+ widget toolkit to implement its user interface, and written in C. Released under the terms of the GNU General Public License v3, PacketSquare-CapEdit is free software.