[Dovecot] Dovecot discards mail over quota

[Markus Schönhaber]

Steffen Kaiser:

> RFC5321 sec 4.2.4
> 
> the same wording about:
> 
>     o  if attempts to deliver the message fail due to permanent
>        conditions, or if repeated attempts to deliver the message fail
>        due to transient conditions, returning appropriate notification to
>        the sender of the original message (using the address in the SMTP
>        MAIL command).

As I see it, no-one in this thread doubts that bounces are spec compliant.

Charles' point - as I understand it and to which I agreed - is the
question *who* should generate a bounce.
IMO the "receiving" MTA *must not* generate a bounce. The reason for
this is not that any part of any RFC I know of does say so, but because
of the simple fact that the receiving MTA very likely is *not able* to
send a useful bounce since chances are that the sender address (i. e.
the address the bounce should be sent to) is faked anyway. Accepting a
mail and generating a bounce later will eventually make you a source of
backscatter and get you blacklisted. The exception to this rule
obviously is the case when you relay mail for your users (which is a
different story anyway since you are the "sending" and not the
"receiving" MTA).

> Which comes down to Timo's original question, in order to remove the 
> notification of Dovecot's deliver in favor of returning the proper exit 
> code to let the MTA handles the stuff, seems to be good.

...if the MTA can find out about deliver's exit status before the SMTP
transaction is completed...

Regards
  mks