check_mailq plugin can be used to monitor the mail queue of a mail server for e-mails that have not yet been delivered.
check_mailq runs the program
mailq of the mail service installed. Unfortunately each MTA interprets the mail queue differently, so the plugin can evaluate only mail queues from mail services that the programmer has taken into account. These are, specifically:
check_mailq plugin has the following options:
If there are at least
mails in the mail queue, the plugin gives a warning.
As soon as there are at least
of mails in the queue waiting to be delivered, then the critical ...