"Nagios Core is obsolete." Fact: Thousands of companies still run Core. It is stable, lightweight, and totally free. Final Verdict There is no unlimited, completely free version of Nagios XI for production environments beyond 7 hosts. However, the official free 7-host license is perfect for small deployments or learning. For unlimited free monitoring, switch to Nagios Core or consider modern alternatives like Zabbix or Prometheus (which are also free and open source).
The short answer is: However, there is an official free tier that is very generous for small environments, and there is always the original Nagios Core for those who want 100% free and open-source software. nagios xi free
Here is the breakdown of what "free" actually means in the Nagios ecosystem. Nagios Enterprises offers a Free License of Nagios XI. This is not a trial; it is a permanently free license, but it comes with specific limits. "Nagios Core is obsolete