Wireshark is the world's foremost network protocol analyzer. It lets you see what's happening on your network at a microscopic level. It is the de facto (and often de jure) standard across many industries and educational institutions. Wireshark development thrives thanks to the contributions of networking experts across the globe. It is the continuation of a project that started in 1998.
Hamster is a tool or "sidejacking". It acts as a proxy server that replaces your cookies with session cookies stolen from somebody else, allowing you to hijack their sessions. Cookies are sniffed using the Ferret program. You need a copy of that as well.
HexInject is a very versatile packet injector and sniffer, that provide a command-line framework for raw network access.
Test for SMTP user enumeration (RCPT TO and VRFY), internal spoofing, and relay.
mitmproxy is an SSL-capable man-in-the-middle HTTP proxy. It provides a console interface that allows traffic flows to be inspected and edited on the fly. Also shipped is mitmdump, the command-line version of mitmproxy, with the same functionality but without the frills.
ohrwurm is a small and simple RTP fuzzer that has been successfully tested on a small number of SIP phones.
A Java based HTTP/HTTPS proxy for assessing web application vulnerability. It supports editing/viewing HTTP messages on-the-fly. Other featuers include spiders, client certificate, proxy-chaining, intelligent scanning for XSS and SQL injections etc.
