OpenNMS

OpenNMS is a free and open-source network monitoring and network management platform written in Java. It provides fault management, performance data collection, service monitoring, event processing, and topology mapping. The project was started in July 1999 and registered on SourceForge as project 4141 in March 2000, making it one of the oldest open-source network management platforms.

OpenNMS is released under the AGPLv3. The OpenNMS Group provides commercial support, training, and an enterprise distribution called Meridian. The project itself is governed by The Order of the Green Polo (OGP), a community organization separate from the commercial entity.