Out of curiosity would it be possible to configure dovecot in such a way that if a message had been accepted by postfix because it couldn't check quota the message was delivered anyway, despite being over quota?
I'd much rather that then risk backscatter.
(I used to have quotas, but with the size of disks I've found it easier to simply have a "clue bat”approach and a reasonable max-message size. When a user gets "too much”mail ask them to purge their older mails with attachments.
Granted, that's probably less workable than quotas for a large user base, but for a period of time I did automate these notices by listing users total storage and sending a heads-up message when they got over a specific number. Granted, that was in the days where a 100MB mail store was a reasonable limit.
-- My main job is trying to come up with new and innovative and effective ways to reject even more mail. I'm up to about 97% now.
On Feb 27, 2018, at 06:18, Karol Augustin <karol@augustin.pl> wrote:
The issue you might encounter with this setup is that if both of your dovecot nodes are unreachable Postfix will accept the e-mail and try to deliver it. When the nodes come online it will fail if the user is over quota and generate bounce to the envelope sender of the message, which might produce backscatter.
I resolved this problem by keeping quota information in Mysql table and using custom policy server to check if user is allowed to receive more e-mail.