Light-weight system monitor for X
A Java based fault and performance management system
free netflow analyzer
Snare Enterprise: bit.ly/Snare-Trial
Monitorix is a system monitoring tool
Show devices in a lan
IP Monitor notifies you when your public IP address changes
SSH Java client GUI for Unix, Linux administration and monitoring
Monitoring of websites with spider and email notifications
A simple packet sniffer for local networks
Free Accountability Software
Web based management tool for unixes
Monitoring your infrastructure for free.