HttpWatch : An HTTP Viewer and HTTP Sniffer for IE and Firefox
Vaurien : 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...
LibreNMS : A fully featured network monitoring system that provides a wealth of features and device support.
Sitespeed.io : Sitespeed.io is an open source tool that helps you analyze and optimize your website speed and performance based on performance best practices. It col...
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.