Nagios Support Forum

I'm currently using Nagios XI, and I have configured three states of alerts: CRITICAL, WARNING, and OK. However, I have a specific requirement to add a custom hard state called FATAL for extreme issues, such as when the server or a specific component (in this case, a Java jar component) is down. Presently, when the host is down, I receive a "DOWN" message, and when the component is down, I receive a "URL Status is CRITICAL" notification. But I want to modify it to display "URL Status is FATAL" instead. I would like to know if it's possible to add this custom state in Nagios and how I can accomplish it.

Nagios sets service/host status based on the return value (0-3) of the check plugin. The text output is meaningless to the alert status.
You can edit the plugin if it's a script, or edit the source and recompile if it's a binary. You could use the negate command to change critical text to fatal.