Zeek is a powerful network analysis framework
terminal based packet sniffer
LumoGate is a Windows Wifi Hotspot Management Software
Visual Syslog Server for Windows with a graphical user interface.
Free Accountability Software
Easy-to-use C++ library for various SNMP tasks
Open Source BGP Looking-glass
vMotion Detector for Linux & Windows Platforms
IDS + IPS for RouterOS (mikrotik)