Open Source Monitoring System for performance and availability.
Nagios Open Source network monitoring software - The Standard In ITM
A Java based fault and performance management system
Monitoring and reporting web gui for Bacula
Xplico is a Network Forensic Analysis Tool (NFAT)
Easily monitor network infrastructure services
Real time monitoring for embedded devices
Real time monitoring : RPi-Monitor always keep an eye on your computer
Tools to help you control IT systems and escape their control over you
Is your host up or down?
A simple cacti viewer for smartphones
Monitoring your infrastructure for free.