What is NRPE :
NRPE allows you to remotely execute Nagios plugins on other Linux/Unix machines. This allows you to monitor remote machine metrics (disk usage, CPU load, etc.).
If, when starting NRPE, zou get something like this :
# ./check_nrpe -H 10.10.10.41 -c check_mailq
./check_nrpe: error while loading shared libraries: libssl.so.4: cannot open shared object file: No such file or directory
That means that your NRPE lacks a Nagios part. And it can’t be fetched from a general repositiry. I had to get each package separately from here : http://pkgs.repoforge.org
And here are the packages that you need :
Add nrpe as a tar.gz format, and install it.
Put there a latest version of check_nrpe script, instead of the old one, in /usr/local/nagios/libexec.
# ./check_nrpe -H 127.0.0.1
If it still will not pass, ond the client machine check /etc/nagios/nrpe.cfg, if you Nagios server may pass to the client (and check iptables too!).