NMIS — Network Management Information System — was created in 1999 by Keith Sinclair of Sinclair InterNetworking Services as a practical tool for fault and performance management of IP networks. Released as open source software, NMIS gained rapid adoption across the network management community for its flexibility and depth, covering SNMP polling, threshold-based alerting, and performance graphing via RRDtool.
Over the following decade NMIS grew into one of the most widely deployed open source network management systems in the world, with active community contributions and adoption across service providers, enterprises, and government organisations globally.
In 2010, Opmantek was founded by Danny Maher to build a commercial ecosystem around NMIS, and in early 2011 Opmantek acquired the intellectual property for NMIS, committing to keep the core software free and open source. Under Opmantek, NMIS continued to evolve through successive major versions alongside a broader product suite including Open-AudIT for network discovery.
In December 2021, Australian cybersecurity company FirstWave Cloud Technology acquired Opmantek. At that point NMIS was in use by 1000's of organisations across countless countries. FirstWave continues to maintain NMIS as open source software, available on GitHub.