Zabbix - Track, record, alert and visualize performance and availability of IT resources

Nagios - Complete monitoring and alerting for servers, switches, applications, and services

Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.

Gitwin - Enable your Windows system as a powerful and secure Git repository. Supports ssh, http(s) transports. Gitweb with highlighter and gravatar support available.

FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.

LANState - LANState - Network Mapper and Device Monitor