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From: Aaron Clausen on 19 Apr 2010 13:34
This has probably been asked a hundred times before, but a client of
mine has requested the ability to reject emails if their spam score is
above a certain score, rather than marking it as spam. Is this a
possibility with Postfix?

--
Aaron Clausen
mightymartianca(a)gmail.com

From: Sean Reifschneider on 19 Apr 2010 13:42
On 04/19/2010 11:34 AM, Aaron Clausen wrote:
> This has probably been asked a hundred times before, but a client of
> mine has requested the ability to reject emails if their spam score is

The problem is that this has to happen after the DATA phase, which is well
after the RCPT phase. If there are multiple recipients, and their
anti-spam settings disagree on what to do with the message, what do you do?

It would be nice if you could report the status for each recipient, but
SMTP doesn't include that provision.

Figuring that part of it out is the hardest part of rejecting spam in that
case.

Sean
--
Sean Reifschneider, Member of Technical Staff <jafo(a)tummy.com>
tummy.com, ltd. - Linux Consulting since 1995: Ask me about High Availability

From: Noel Jones on 19 Apr 2010 13:51
On 4/19/2010 12:34 PM, Aaron Clausen wrote:
> This has probably been asked a hundred times before, but a client of
> mine has requested the ability to reject emails if their spam score is
> above a certain score, rather than marking it as spam. Is this a
> possibility with Postfix?
>

Yes, but the filtering must be done before the mail is queued.
That means either using either a milter or a
smtpd_proxy_filter as the glue between the filtering program
and postfix.

If you reject mail using a postfix content_filter, you become
a backscatter source and will likely be blacklisted if your
volume is more than negligible. Never reject mail when using
a postfix content_filter.

Note that using a resource-intensive process such as
spamassassin pre-queue reduces the peak throughput of mail,
and may not be suitable for all sites.

There are several milters that can use spamassassin, search
google. Amavisd-new works well as a smtpd_proxy_filter.

For something a little lighter-weight than spamassassin, you
might investigate the j-chkmail milter.

-- Noel Jones

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