dovecot - Jan 2015 - LDA input validation

St?phane Cottin writes:
>> You're stilling going to lose contents.  If dspam fails, the mail
>> is dumped, the LDA returns exit code 75, and the MTA will probably
>> issue a bounce Email to the sender.
>
> from dovecot-lda man page :
>
> 75  A  temporary  failure.  This  is  returned  for  almost all failures.
See the log file for
>           details. (EX_TEMPFAIL)
>
> The mta keep the mail and retry delivery later, which is what I need.
Ah, my mistake.  But ...
> I don't want to deliver email on dspam error, I prefer TEMPFAIL and
> future retries, so I have a chance to fix the issue later without
> loosing or deliver unprocessed mails
... you only have a limited time to fix it.  Depending on the sending
MTA's retry schedule, you might have only a few days or less to to deal
with it before the sending MTA stops trying.

If it's important not to lose mail, then the deliver on failure strategy
would be more appropriate.  You can even copy the input message that
caused dpam to crash to an inspection queue for later perusal.

Joseph Tam <jtam.home at gmail.com>

> Le 26 janv. 2015 ? 12:03, Joseph Tam <jtam.home at gmail.com> a ?crit
:
> 
> St?phane Cottin writes:
> 
>>> You're stilling going to lose contents.  If dspam fails, the
mail
>>> is dumped, the LDA returns exit code 75, and the MTA will probably
>>> issue a bounce Email to the sender.
>> 
>> from dovecot-lda man page :
>> 
>> 75  A  temporary  failure.  This  is  returned  for  almost all
failures. See the log file for
>>          details. (EX_TEMPFAIL)
>> 
>> The mta keep the mail and retry delivery later, which is what I need.
> 
> Ah, my mistake.  But ...
> 
>> I don't want to deliver email on dspam error, I prefer TEMPFAIL and
>> future retries, so I have a chance to fix the issue later without
>> loosing or deliver unprocessed mails
> 
> ... you only have a limited time to fix it.  Depending on the sending
> MTA's retry schedule, you might have only a few days or less to to deal
> with it before the sending MTA stops trying.
We hopfully are notified whitin a few minutes when something's wrong in mail
delivery, having a few days to fix is far more than needed.
> 
> If it's important not to lose mail, then the deliver on failure
strategy
> would be more appropriate.  You can even copy the input message that
> caused dpam to crash to an inspection queue for later perusal.
We do not have dspam crashes caused per email contents, they always are system(
disk errors, oom kill,?) , clamav or database issues.
Anyways, having a copy of the input message somewhere, whatever it's
unrelated to the error is a good advice, we'll think about it.
> 
> Joseph Tam <jtam.home at gmail.com>