Zabbix - Track, record, alert and visualize performance and availability of IT resources
Gitwin - Enable your Windows system as a powerful and secure Git repository. Supports ssh, http(s) transports. Gitweb with highlighter and gravatar support available.
Observium - Observium
LANState - LANState - Network Mapper and Device Monitor
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Icinga - Icinga is a fork of Nagios and is backward compatible.