Subject: Blacklist usage in zmailer

From: Mike Acar <[email-masked]>
Date: Tue, 27 Aug 2002 13:33:53 +0200

Hi all,

Some time ago we started using various anti-spam blacklists
(relays.osirusoft.com, relays.ordb.org, and dialups. mail-abuse.org) and
happily these seem to have cut down on our incoming spam. Unfortunately
we have an increasing number of customers who find themselves on the
blacklists and apparently have no reasonable way of getting off (i.e.,
they're in Asia).

Therefore I wonder if it's possible to get some assistance from the
list; I haven't found the zmailer docs particularly helpful in this
regard.

I'd like to be able to make exceptions for mail destined to particular
addresses (e.g. our sales mailbox) or from certain servers. Ideally the
messages and connections would still be checked against the blacklist
and the outcome logged, but the message processed regardless.

Is this possible? Anybody have example smtp-policy.src snippets?

-- 
Brilliance and gorgeousness                        |   Mike Acar
And we tell ourselves we don't want the treasures  |   [email-masked]
But we hate the glass anyway                       |
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From: Rik van Riel <[email-masked]>
Date: Thu, 29 Aug 2002 11:13:47 -0300 (BRT)

> addresses (e.g. our sales mailbox) or from certain servers.

I'd also like to be able to do something like this. To be
more specific, I _always_ want to accept email to abuse@
and postmaster@ addresses, while filtering email to the
other addresses with DNSBLs.

As an aside, I'm also thinking of adding an option to
smtpserver to refuse email when the HELO string doesn't
resolve ;)

kind regards,

Rik
-- 
Bravely reimplemented by the knights who say "NIH".

http://www.surriel.com/		http://distro.conectiva.com/

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From: [email-masked] (Alexey Lobanov)
Date: Thu, 29 Aug 2002 18:28:17 +0400

Hello.

> and postmaster@ addresses,

Moreower, your wish is in perfect accordance with rfc2821 4.5.1. "...SMTP systems are 
expected to make every reasonable effort to accept mail directed to Postmaster from any 
other system on the Internet..."

> while filtering email to the other addresses with DNSBLs. 

A.L.

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From: Tomaz Borstnar <[email-masked]>
Date: Thu, 29 Aug 2002 20:58:29 +0200

>smtpserver to refuse email when the HELO string doesn't

Bad, bad, bad. You wont like the results probably. Or you dont care about 
lost mail? Not all of that is spam, you know?

----
Tomaz Borstnar <[email-masked]>
"Love is the answer to the final question you ask" - Unknown

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From: "Alexey Lobanov" <[email-masked]>
Date: Fri, 30 Aug 2002 00:14:37 +0400

Hello.

> lost mail? Not all of that is spam, you know?

Postfix does have quite full set of HELO rules:

#   reject_non_fqdn_hostname: reject HELO hostname that is not in FQDN form
#   reject_invalid_hostname: reject HELO hostname with bad syntax.
#   reject_unknown_hostname: reject HELO hostname without DNS A or MX record.

My experience shows that first rule is OK. Only client (and spammer) 
workstations say "HELO Default", etc. Naturally, direct or authorized clients 
bypass checking. But even the second rule is too restristive for guests: about 
50% of legitimate corporate MS-Exchange servers compose their self-names from 
NetBIOS name (where underscore "_" is a must according to MS traditions) and 
valid domain. So, neither formal nor real DNS-compliance tests are feasible.

Alexey

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