Wireshark : 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 fac...
LibreNMS : A fully featured network monitoring system that provides a wealth of features and device support.
Wapiti : Wapiti allows you to audit the security of your web applications.
It performs "black-box" scans, i.e. it does not study the source code of the applica...
Vaurien is basically a Chaos Monkey for your TCP connections. Vaurien acts as a proxy between your application and any backend.
You can use it in your functional tests or even on a real deployment through the command-line.