LDA input validation

[Stéphane Cottin]

> Le 26 janv. 2015 à 12:03, Joseph Tam <jtam.home at gmail.com> a écrit :
> 
> 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>