I have inherited a Nagios system. All of the servers appear to be running the same configuration, with NSClient+ and Nagios Event Log Agent.
On some of the servers, when an error is written to the Event Log, Nagios will show the error in its logs but not report the error anywhere.
On these same servers, when the hearbeat check runs, the Event Log shows the following message:
Warning: Passive check result was received for service ‘EventLog Agent’ on host ‘ussmcapp’, but the host could not be found!
Everything looks the same on the nagios.cfg file between the servers do trigger Nagios Alerts and those that dont.
Any help would be greatly appreciated.