Free and Open Source network access control (NAC) solution
Full-featured enterprise network management tool
FlowViewer is a web-based netflow data analysis tool.
free netflow analyzer
OPTOSS Next Gen Network Management System (NG-NetMS)
Track your ARP/MAC table changes and so much more
Open Source SIEM
MitM pentesting opensource toolkit
Real time monitoring : RPi-Monitor always keep an eye on your computer
Poll JMX attributes from Java based applications with Nagios
Build custom filter for your network based off of common communication
Web based management tool for unixes
HTTP header aggregation tool
A detailed user action logging engine