October 7th, 2011
OSX Server comes pre-packaged with Dovecot one of the best IMAP services out there and one of the most extensible and flexible in my opinion. That is its flexible and extensible as long as you know how to configure Dovecot which most OSX Server Administrators are not. I had a conversation with a co-worker not too long ago about being an OSX Server Administrator and I joked that Apple made great hardware and a great OS but most if not all of the services under the hood for Web, Mail, Mailing Lists, etc… were all borrowed open source technologies and that Apple really does not offer any sort of support base for the open source technologies that they use. However without these pieces of software their entire PR Campaign would hold no water. What I praise Apple for is taking these tools and utilizing them and making them easier to use while leaving the ability to tinker and improve these services.
One such service is the topic today, Dovecot. Dovecot is integrated with Server Admin, Apples GUI Server Administration tool. You can set two different kind of notifications to trigger here, a quota notification that will send an email out when someone is over a certain percentage of email quota and an email warning them when they have gone over quota. In my experience it takes more than a couple emails to make a user clean up their inbox.
What I wanted was a way to say, send out an email when a user goes over a specified limit and then send an email every ten percent they go over the original limit. When they reach ten percent before their quota is exceeded increase the email notification rate to one email every percent until they reach their quota and then at that time continue to send an email a day until their quota has been reduced. On top of that I wanted it to also notify me of people who have gone over quota so that I can prove to them that they did indeed get the notification. For me a good solution was having all quota notifications CC’d to our help desk which in turn opened a ticket on the behalf of the offender in a sense sending them two emails each time they went over quota. I am going to cover the necessary steps needed to accomplish this task on your OSX Mail server.
** Note what we are about to do will mean that you will no longer be able to use Server Admin to manage email notifications.
sudo pico /etc/dovecot/dovecot.conf
quota_warning = storage=100%% /usr/libexec/dovecot/quota-exceeded.sh