Nagios Core

Nagios Core at a glance

Nagios Core is the long-established open-source monitoring system, the origin of a large ecosystem of plugins and forks. Nagios Core ships releases in an unhurried cadence plus security fixes; as a monitoring system with credentials and network visibility, keeping it current and hardened matters.

For admins Nagios Core is often customized heavily with plugins and configuration, so upgrades want care — back up the configuration first and test, since config formats and plugin behaviour can shift. The web interface and the monitored systems' credentials make it security-relevant, so keep it off the open network behind authentication. Nagios has had security advisories, so apply security releases promptly. After updating, verify that checks run and notifications fire — a silently broken monitor is dangerous. Many run modern successors (Icinga, Naemon, Checkmk) that share the plugin ecosystem. Track the version and its support status; patchletter surfaces new Nagios Core releases.