This weekend I had the problem that I had to check several hosts on a network
behind NAT with nagios. One solution would be to add portforwardings on the NAT
firewall for each host and use check_nrpe with different port settings from the
nagios machine. This is of course a maintenance nightmare.
The solution that I choose was therefor a little different. I installed nrpe
server and the nrpe plugins on all hosts. Then a portforwarding to port 5666 of
one host (irobot) was added in the firewall. In the nrpe config of irobot I
added the checks for irobot and checks for the other hosts by adding lines like
these to the nrpe.cfg of irobot:
cammand[vacdepot_fs_root]=/usr/lib/nagios/plugins/check_nrpe -H vacdepot -c check_fs_root
In the nrpe.cfg of vacdepot check_fs_root is defined of course.
So I am using nested nrpe calls to get the data I want. The advantage being
that I do not have to have a portforwaring for every host I want to monitor
behind the NAT firewall.
