A network security analysis and monitoring toolkit Linux distribution.
Free UTM appliance: firewall, VPN, WAF and antivirus in one ISO.
Anti Spam SMTP Gateway
Xplico is a Network Forensic Analysis Tool (NFAT)
PotHead
Open Source SIEM
Scalable, distributed monitoring system for high-performance computing
Collects data about network useage using libpcap.
Hierarchical Cluster Engine project
Batch system monitoring and archiving
Monitoring your infrastructure for free.
WatchTower is a cloud server monitoring and management tool
something that writes code for you