You might see an Apache 403 Forbidden Warning error reported in Nagios after a new installation or upgrade to OES 2018 or later.
Figure 17-1 HTTP 403 Forbidden Warning Error
To resolve the issue, you can try the following:
Log in to the server as the root user, open a terminal console, then navigate to the /etc/nagios/objects directory.
In the localhost.cfg file, modify the check_command parameters in the section, “# Define a service to check HTTP on the local machine”:At the command prompt, enter
define service { use local-service ; Name of service template to use host_name localhost service_description HTTP check_command check_http! -e 'HTTP/1.0 200','HTTP/1.1 200','HTTP/1.1 403 Forbidden' notifications_enabled 0 }
Restart Nagios.
rcnagios restart
After a few minutes, verify that the HTTP status for Nagios has been updated to the OK (green) state.
Log in as the root user to OES Remote Manager.
Select Diagnose > Server Health Services, then click Nagios Service Detail.
In the Nagios Authentication Required dialog box, specify your Nagios user credentials, then click OK.
View the HTTP status in the Nagios main dashboard.