[Dovecot] Postfix aliases with quota-status service

[Robert Schetterer]

Am 06.08.2013 20:27, schrieb Timo Sirainen:
> On 6.8.2013, at 20.57, Thomas Leuxner <tlx at leuxner.net> wrote:
> 
>> * Timo Sirainen <tss at iki.fi> 2013.08.06 19:42:
>>
>>> The idea behind quota_grace is that the last mail would be allowed to take the user somewhat over quota (e.g. up to 109% quota usage). On the next mail delivery user is already over quota, so the size of the mail is irrelevant because a mail of any size will be rejected. The initial quota-status implementation didn't even support SIZE extension since I didn't remember it existed.
>>
>> I'm referring to the Postfix side _only_ or the initial SMTP Handshake if you like. My point is that there is no safe way to reject mails at this level *if* the remote server doesn't play nice. I think this was the whole point of writing a policy service for Postfix. I'm not *talking* about quotas that will be handled  by the delivery agents...
> 
> Either you're still misunderstanding me, or vice versa. The quota rejections can be done complete in SMTP side even without SIZE:
> 
> 1) quota at 99% :
> 
> MAIL FROM:<sender at example.com>
> 250 2.1.0 Ok
> RCPT TO:<tss at dovecot.org>
> 250 2.1.0 Ok
> DATA
> ...
> .
> 250 2.0.0 Ok: queued as 12345
> 
> 2) quota is now at 103% :
> 
> MAIL FROM:<sender2 at example.com>
> 250 2.1.0 Ok
> RCPT TO:<tss at dovecot.org>
> 554 5.2.2 User is over quota
> 

Thomas is right in general, thats a general problem with mail quota,
that was the reason why there wasnt some good solution out for long times,

but the dove policy server does i.e reject mail in smtp session if its
allready "assured" that the mailbox is definite ... percent over quota (
configurable by grace parameter ), at that point it does not mater which
size the incomming mail has, it will be i.e rejected anyway
also it honors ( some kind overides ) other quota setting in i.e lmtp or
lda, cause if it wouldnt, a mailbox would never become overquota by
rejecting mail before by lmtp/lda settings




Best Regards
MfG Robert Schetterer

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