Wierd errors when running Nagios3

While setting up Nagios3 I got this error: (Return code of 127 is out of bounds – plugin may be missing). I couldn’t understand what it was because I could run check_nrpe manually from the CLI and other plugins (link check_ping) worked fine. After a lot of looking around it turns out (atleast in Gentoo) nrpe places check_nrpe in another directory (/usr/nagios/libexec/) than where the others are (/usr/lib/nagios/plugins/) (and where $USER1 points). So I just made a symlink and Nagios finally worked.

Another thing that isn’t pointed out very well I think is that servers are generally backwards-compatible with clients (but not the other way around). In my case this means running 3.0.6 on the server and 2.12 on the (etch) clients works fine!