Nagios XI is aimed at a wide audience, from freelancers, SMBs (Small-to-Medium-Business), to large corporations. This makes Nagios’s XI pricing model one of the most flexible. They have a free version, open-source, one-time license and subscription. It is one of the few tools that allows an extreme flexibility (because of its adaptability to plug-ins) on what’s being monitored and alerted for a low cost.
Nagios XI focuses on monitoring. The key IT components that Nagios XI monitors are Network, Infrastructure, and Database. Although the software is easy to install, it will initially take some time to adjust to your requirements. This is because Nagios XI does not auto-discover devices. You have to configure each device that needs to be monitored with a configuration file.