From: Cami (camismweb.co.za)
Date: Tue Jun 01 2004 - 19:55:27 CDT

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

>>A large amount of my userbase is very confused by the From:/To: fields
>>that Postfix inserts.. (especially when they try to reply to the mail..)
>
> Thank you. You understand the problem.
>
> Do you have numbers on how many of such mail is malformed but otherwise
> valid email?

110 million mail messages are spam (+30 million legitimate), of those
almost 5 million have To/From headers that Postfix replaces.. (monthly
statistics)

Having to deal with those clients is quite a headache as previously
we used Exim and then Qmail, and neither had the same behaviour..

Be that as it may, perhaps i'm being over critical and having to
(in my opinion) use the best MTA comes with small burdens and a
lot more positive points..

> And how many of those do have a message-id?

Postfix accepts the mail, injects its own Message-ID and once queued,
the message gets past onto SpamAssassin. SpamAssassin clearly can see
that the Message-ID was added by the wrong machine (part of the default
SA ruleset) and adjusts the SA scoring ..
50_scores.cf:score MSGID_FROM_MTA_SHORT 3.665 3.310 3.167 3.030
Thats *extremely* high and has a very bad effect for legimate
mail entering the system..

> As far as I can tell:
> - mail without a message-id is spam or virus, perhaps a few exceptions

Thats is not quite true.. I done some tagging on mails without
Message-ID's and found that there *is* quite a lot of legimate
mail that does *not* have a Message-ID.. (especially from some
large mailing lists in the past..)

> - adding a message-id is specifically forbidden by rfc2821 when an MTA
> is an intermediate (such as: spammer->MTA1->MTA2->destination when
> postfix is MTA2)
> - currently there's no way (AFAIK) to make postfix NOT add/correct the
> headers despite the MUST NOT as discussed
>
> So therefore I stand by my claim that adding a message-id is wrong. In
> the message itself I stated that opinions and setups may differ so the
> process should be configurable. I regret if my wordings are misinterpreted
> however I have done my homework.

Just so i make my point known, the Message-ID bit is not really an
issue for me.. Its the From:/To: fields that cause the headaches..

Cami

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]