[Dovecot] Dovecot discards mail over quota

[Ulrich Zehl]

On Sun, Jan 18, 2009 at 12:26:46PM -0700, Gary V wrote:
> Just as a matter of interest. On my Postfix system:
> 
> a) Using deliver -e, Postfix bounces the message immediately 5.7.0 ->
> Subject: Undelivered Mail Returned to Sender. Partial body:
> "<test at example.com>: permission denied. Command output: Quota exceeded
> (mailbox for user is full)". Postfix does not retain the message.
> 
> b) quota_full_tempfail=yes: defers the message with 4.3.0. If the user
> makes room for the message, then it will eventually be delivered. If
> they don't, then _eventually_ a bounce will be sent. In this case the
> bounce is less informative. Partial body: "<test at example.com>:
> temporary failure". In the case where the message is not delivered,
> using default settings in Postfix, the sender will be notified 5 days
> after they sent the message.
> 
> c) For over quota with a+b, it behaves the same way as b, but the
> bounce notice will be more informative: Partial body:
> "<test at example.com>: temporary failure. Command output: Quota exceeded
> (mailbox for user is full)".
> 
> I would say this is expected.

You can also quota_exceeded_message to something like "4.2.2 Mailbox full"
(or "5.2.2 ..."). This works whenever -e is specified, i.e. for a) and c),
and you use Postfix 2.3 or later (see pipe(8)).

> Each of the four possibilites has advantages and disadvantages, and
> personally I think a) might be closest to "doing the right thing", but
> it would be cool to have the option of deferring the mail (using
> option a+b) and additionally have deliver immediately send a message
> to the sender notifying them that their mail has been delayed due to
> the recipient being over quota. Something like:

This is also easy with Postfix, if you use delay_warning_time (see
postconf(5)).