High performance ping tool
SQL operating system instrumentation and monitoring framework
The Network UPS Tools repository
WinDivert: Windows Packet Divert
Open Source Monitoring System for performance and availability.
Nagios network monitoring software is enterprise server monitoring
Manage and interpret IPMI systems with common a software tool
VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Xymon monitors your hosts, your network services, and everything else.
Intelligently block brute-force attacks by aggregating system logs
Firewall log analyzer
High capacity syslog data collection, filtering, and management.
ICMP-based network bandwidth measurement tool
A Swiss army knife for your daily Linux network plumbing