Nagios is a popular open source computer system and network monitoring software application. It watches hosts and services, alerting users when things go wrong and again when they get better.
Nagios, originally created under the name NetSaint, was written and is currently maintained by Ethan Galstad, along with a group of developers actively maintaining both official and unofficial plugins.
N.A.G.I.O.S. is a recursive acronym: "Nagios Ain't Gonna Insist On Sainthood"[3], "Sainthood" being a reference to the original name of the software, which was changed in response to a legal challenge by owners of a similar trademark and "agios" just happens to be modern Greek for saint.
Nagios was originally designed to run under Linux, but also runs well on other Unix variants. It is free software, licensed under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.
