For this example the server host IP is 10.0.0.5 and the client host IP is 10.0.0.6
Installed the nagios-nrpe-server on the client host: aptitude install nagios-nrpe-server
Verified process was running: netstat -an | grep 5666
Logon to the Nagios Server host and execute: /usr/lib/nagios/libexec/check_nrpe -H 10.0.0.6
CHECK_NRPE: Error - Could not cocmplete SSL handshake.
Tweaked the Ubuntu's nrpe config on the client host: vi /etc/nagios/nrpe.cfg
allowed_hosts=127.0.0.1
to
allowed_hosts=10.0.0.5 (my Nagios server host IP)
This is needed since the nagios plugin was installed without inetd/xinetd.
Restarted nagios plugin: /etc/init.d/nagios-nrpe-server restart
Tested Again on the Nagios Server:
/usr/local/nagios/libexec/check_nrpe -H 10.0.0.6
--> NRPE v2.8.1