[Dovecot] Dovecot discards mail over quota

[Gary V]

On 1/18/09, Sahil Tandon wrote:
> On Sun, 18 Jan 2009, Gary V wrote:
>
> > On 1/17/09, Timo Sirainen wrote:
> >  > On Jan 17, 2009, at 2:36 PM, Gary V wrote:
> >  > > Then a bounce is created stating the mail was rejected:
> >  > >
> >  > > Your message to <test at example.com> was automatically rejected:
> >  > > Quota exceeded (mailbox for user is full).
> >  > >
> >  > > Question: is it possible (without changing code) to alter this to
> >  > > where deliver would instead tempfail or something. Somehow it seems
> >  > > wrong to me to tell the MTA that everything is good, and then silently
> >  > > discard messages - regardless of the fact dovecot creates a bounce.
> >  > > This is not necessarily ideal either, but I _am_ wondering if this is
> >  > > configurable or not.
> >  > >
> >  >
> >  > a) deliver -e
> >  >
> >  > b) quota_full_tempfail=yes
> >  >
> >  > c) a+b
> >  >
> >
> > 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.
> >
> > 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:
>
> I prefer a) because it does not involve backscatter in the case of spoofed
> sender addresses.
>
> --
> Sahil Tandon <sahil at tandon.net>
>

Hmm, in my test, mail is not rejected during smtp conversation, so as
far as I can see, there is no prevention of backscatter. Posftix
creates a bounce after the fact and sends it to whomever the sender is
(or at least attempts to).

As a side note:
It looks like Couier/Maildrop uses the functional equivilent of a+b.
At least when using Postfix, the message is deferred with a
descriptive error:  "temporary failure. Command output: maildrop:
maildir over quota." I have not looked to see if this is configurable
or not. I would assume it is, but have not checked into it.

-- 
Gary V