Nagios Support Forum

I have a Nagios core server version 3.2.3 (yes, I know it is old, but it works beautifully), and I want to monitor Sendmail mailq on 3 remote servers.
I have tried with check_mailq, I have copied it on a Sendmail server, but it will not execute (libraries), and it requires Nagios installation on mail server. This I will not do.
Anz other ideas? Please some links!
I have tried on Internet (of course!), but found nothing useful.

Have you tried running check_mailq through nrpe?

No. I was thinking more in terms of SMTP.
But the problem is that script check_mailq.pl can not run on the remote mail server :
# ./check_mailq
Can't locate utils.pm in @INC (@INC contains: nagios/plugins /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at ./check_mailq line 36.
BEGIN failed--compilation aborted at ./check_mailq line 36.

I do not want to put Nagios on this server, just to monitor its mailq.

You do not need to install Nagios there, just NRPE which is one of the available agents. Once you have installed NRPE, and the plugins package. You should place the check_mailq plugin in the /usr/local/nagios/libexec directory that is created "barring that this is a RHEL or CentOS based system" then the plugin should work fine.

http://assets.nagios.com/downloads/nagi ... _Agent.pdf

Nagios core is not needed for utils.pm, nagios-plugins is.
https://www.nagios-plugins.org/