LibreNMS

LibreNMS is a network monitoring system that automatically discovers devices and tracks them over SNMP. It is built with PHP and MySQL and supports many kinds of network gear and operating systems, such as Cisco, Linux, FreeBSD, Juniper, Brocade, Foundry and HP equipment. Administrators use it to keep an eye on routers, switches, servers and other networked equipment.

The project describes itself as a community effort that welcomes contributions, puts users' needs first and aims to be friendly, using the Debian Social Contract as the basis of its priorities. The code is a Laravel application, with RRD-based graphing mentioned in the repository topics, and extensive documentation is published on the project site.

The tagline calls it a GPL-licensed system, although GitHub reports the license as 'Other'. LibreNMS is installed on your own server, and there is no hosted version provided by the project. It suits network administrators, ISPs and IT teams that want a free alternative to commercial network monitoring suites.