The best free alternative to LibreNMS is Zabbix, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to LibreNMS and many of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to LibreNMS are Nagios (Freemium, Open Source), Spiceworks Help Desk (Free), Icinga (Freemium, Open Source) and PRTG Network Monitor (Freemium).
Easy to use configuration web interface for nagios and neamon. openITCOCKPIT is a perfomant monitoring system with support for distributed monitoring (Satellites), REST API, nice dashboards, maps, graphs and a modular concept for easy customization.
OpenNMS is an enterprise grade network monitoring and network management platform developed under the free software or open source model. It consists of a community-supported, free-software project as well as an organization offering commercial services, training and support.
The alerta monitoring system is a tool used to consolidate and de-duplicate alerts from multiple sources for quick ‘at-a-glance’ visualisation. With just one system you can monitor alerts from many other monitoring tools on a single screen.
Centreon is a GUI built ontop of Nagios. Features include: monitoring your servers, active elements and applications. real-time operating and component management console. maintenance and support for your whole platform by the solution publisher.
LANState is a simple NMS with the network topology mapping and device monitoring functions. Add hosts to a graphical network map and monitor their state in the real time. Receive failure notifications when hosts and services go down.