Host not found


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.


Is there a host definition in nagios for the hosts which it says couldn’t be found?


There is a definition for the all of the servers in the Nagios.cfg, both the ones that are working and the ones that are not working. They all appear to be the same.


So do you have multiple nagios servers and multiple nagios monitored systems? (many to many)
… or just a single central nagios instance? (many to one)

You give the impression that everything is lumped into a single nagios.cfg file on the nagios server(s) - there isn’t a missing closing bracket in there somewhere?


There is no one definition for all servers in the nagios.cfg, both those working and those who do not work. They all seem to be the same. In these servers, when the control is run heartbeat.