LibreNMS is a free network monitoring system that keeps polling routers, switches, servers and firewalls to draw their traffic graphs and warn you when something degrades. The project started in 2013 as a fork of the last Observium release published under the GPL, at the time Observium moved to a paid edition. The LibreNMS authors state in their documentation that this commercial decision was not what drove the split, but rather a difference in priorities: they wanted a project steered entirely by its community. The code is released under the GPL version 3 and no company sells a commercial edition.
What LibreNMS is for
Everything starts with SNMP, the protocol almost every piece of network equipment speaks. You add a first device, and LibreNMS uses it to discover the others by reading CDP, LLDP and FDP tables, OSPF and BGP neighbour lists or simply the ARP cache. Every recognised device is polled at regular intervals, its counters are stored and turned into graphs you can browse from a web browser: port throughput, CPU load, memory, temperature, power supply status, depending on what the device exposes. The list of supported vendors is long, and the community keeps adding new models.
Alerting sits on top of this collection. Rules define what deserves a notification, for instance a port going down, a saturated link or an unreachable device, and messages go out by email, Slack, IRC or many other channels. An API covers the whole data set, which makes it possible to feed other tools or drive LibreNMS from scripts. The project site also lists port billing, useful to hosting providers that re-invoice bandwidth, distributed polling to spread the load across several machines, an agent for Unix servers, and integrations with Oxidized or RANCID for configuration backups, SmokePing for latency and NfSen for flows. Authentication can go through LDAP, RADIUS or Active Directory.
Among its neighbours in this software library, LibreNMS holds a precise spot. ntopng examines the content of the traffic, flow by flow, whereas LibreNMS measures volumes and states through SNMP. NetBox records what the network should be, while LibreNMS observes what it actually is, and the two work well together. Observium remains the closest relative, with a shared ancestry but a closed model for its advanced features.
Who is it for?
LibreNMS is aimed at administrators of corporate networks, internet service providers and hosting companies, campus IT teams, and managed service providers that watch over their customers’ infrastructure. It also suits an enthusiast who wants to keep an eye on a home network, provided they accept running a server.
Its demands are real. SNMP has to be enabled and secured on every device, which takes time on a mixed estate. The server relies on PHP, MariaDB and a web server, with, according to the documentation, PHP 8.4 as the minimum and 8.5 recommended, and it needs regular upkeep. Beyond a few hundred devices, distributed polling becomes necessary. LibreNMS does not manage device configurations, does not map application flows and is not a source of truth: for those needs, look at Oxidized, ntopng and NetBox respectively.
Download LibreNMS safely
There is no file to download in the usual sense: LibreNMS is installed by fetching the code from the librenms/librenms repository on GitHub and following the official guide on docs.librenms.org, which covers Ubuntu 24.04 and 26.04, Debian 12 and 13, and Rocky Linux, AlmaLinux and Oracle Linux 8 to 10. The project ships a release every month, numbered by year and month, and 26.9.1.1 came out on 22 September 2026 according to the releases page. An official Docker image, based on Alpine Linux and nginx, is available on Docker Hub and on quay.io, with a sample compose file in the librenms/docker repository. The documentation states that prebuilt virtual machines are no longer supplied or maintained, and recommends Docker instead.
The software is entirely free, with no paid edition and no official commercial support. That is exactly why LibreNMS virtual machine images found on third-party sites deserve suspicion: they often ship with default passwords everyone knows and an outdated copy of the code. The built-in automatic update mechanism also assumes an installation made from the official repository.
Frequently asked questions
Is LibreNMS free?
Yes. LibreNMS is released under the GPL version 3, and its documentation says no paid version is planned. Support comes from the community, on the project forum and Discord.
What is the difference between LibreNMS and Observium?
LibreNMS grew out of the last Observium release published under the GPL. Since 2013 the two projects have evolved separately: Observium keeps some features for a paid edition, while LibreNMS stays fully free and accepts contributions from anyone. A migration script moves an installation from one to the other.
Does LibreNMS run on Windows?
No, the server has to run on Linux, either as a classic installation or in Docker. The interface, however, works from any browser, and the monitored devices can be Windows servers as long as they expose SNMP.
