Nagios Open Source network monitoring software - The Standard In ITM
Ncurses-based monitoring application for wireless network devices
The Network UPS Tools repository
Performance Co-Pilot
A Swiss army knife for your daily Linux network plumbing
SQL operating system instrumentation and monitoring framework
High performance ping tool
Open Source Monitoring System for performance and availability.
Intelligently block brute-force attacks by aggregating system logs
VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
ICMP-based network bandwidth measurement tool
Powerful, open-source network protocol analyzer
Manage and interpret IPMI systems with common a software tool
Network Load Balancer and Application Security
Firewall log analyzer
Very fast network stress tool
Delay-Tolerant Networking suitable for spacecraft and ground
Free UTM appliance: firewall, VPN, WAF and antivirus in one ISO.