Snare Enterprise: bit.ly/Snare-Trial
NetFlow iptables module for Linux kernel
Xplico is a Network Forensic Analysis Tool (NFAT)
Pinger alert, STATICTICAL TABLES, send EMAILs or SMS by SMS GATEWAY
Apache module for SNMP monitoring
Open Source SIEM
Bandwidth monitor and rate estimator
Energy and environmental monitoring of the server room
Scalable, distributed monitoring system for high-performance computing