[TUTORIAL] Send notification email if some mail in Queue Administration with Reason "452..." or over threshold of number of messages

[poetry]

Hello,

We are seeing that a good indication that something is not working when messages are starting to accumulate on our incoming mail filter.
Is it possible to create some rule so we would be notified if messages in Queue reach a specific threshold like more then 50 messages in Queue waiting for delivery or if we can set strings that will match the reason for example here is one on the image below


Thank you!

 

[hata_ph]

Use system monitoring tool like nagios to monitor your pmg system load or mail queue.

 

[poetry]

I managed to do this with a simple bash script and it does exactly what I wanted. I modified the original script to send information about the queue in the body.
This link was very helpful: https://mailmum.io/posts/monitoring-postfix-email-queue-with-push-notifications/
Here info about the script and some commands:

apt install gawk
whereis -l postqueue
chmod +x /usr/local/sbin/mailqueue_size.sh

Script:
nano /usr/local/sbin/mailqueue_size.sh

#!/bin/bash

mailq_count="$(/usr/bin/mailq | /usr/bin/tail -n1 | /usr/bin/gawk '{print $5}')"
mailq_reason="$(/usr/sbin/postqueue -p)"

# If variable is empty, then the queue is empty -> set it to zero
if [ -z "$mailq_count" ]; then
  mailq_count=0
fi

if [ "$mailq_count" -gt 20 ]; then
  echo " ${mailq_reason} " | /usr/bin/mail -s "${mailq_count} <- this many messages are waiting for delivery on server.example.com " example@example.com
fi

Cron:
nano /etc/cron.d/mailqueue-watchdog

*/5 *  * * *   root    nice -n 19  /usr/local/sbin/mailqueue_size.sh

 

[qw3rty]

Thanks for sharing the idea.

I wonder if there is a command to add a user to the blacklist to immediately block the sender when the number of messages in the queue is too large.