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From: Wietse Venema (wietseporcupine.org)
Date: Tue May 06 2008 - 14:06:17 CDT
> On Mon, 5 May 2008, Wietse Venema wrote:
> > > Is there a way/would it be feasible to design a Postfix service, which
> > > could be called to query the next-hop destination *before* accepting the
> > > mail? It could be a standard SMTP client issuing always
> > >
> > > MAIL FROM:<foosrc> SIZE=xxx
> > > RCPT TO:<bardst>
> > Use an access map (updated a few times a day) or policy server (use
> > a cache for already looked up information).
> I must have a blind spot, but I don't get the access map idea. What should
> update the info (what kind of info?) in the access map? As mouss
> suggested, a policy daemon could query the remote destinations about the
> quota limits of the user, so I'll look into this possibility.
The access map (either flat file or *SQL database) replies with
554 5.2.2 Mailbox full
when the user's mailbox is full.
> But isn't there a simple way to get the delivery results out of the smtp
> process of Postfix (I mean besides monitoring the log file) and feed it
> into a process or database? That way an approximate solution could be set
> up: if n unsuccessful delivery attempts detected in a row, then stop
> delivering to the recipient (reject) for a couple of hours.
I already mentioned this in the text that you deleted from my reply.
The feature is called reject_unverified_RECIPIENT. The information
comes from the Postfix SMTP client when it talks to the next-hop
host, and the information is stored into $address_verify_map. You
control the process with the address_verify_negative_* and the