Re: [Exim] .forward files and spam counterfeits

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Author: John (TJ) Penton
Date:  
To: Alan J. Flavell
CC: Exim users list
Subject: Re: [Exim] .forward files and spam counterfeits
On Thu, 27 Nov 2003, Alan J. Flavell wrote:

> 1. Spammer sends mail to victim@??? with the envelope
>
> 2. the mailer at elsewhere.example obeys the user's .forwarding
> arrangements and offers the mail to us, with their local address here
> as recipient, and their elsewhere.example address as envelope sender.
> Sometimes (but not always) their elsewhere.example address also
> appears in the To: header.
>
> 3. We recognise the stuff as spam, and refuse to accept it.


Suggestion:

Don't refuse the spam, simply drop it silently. No bounce message will be
generated.

This does have the disadvantage that false-positive spam detections go
undetected by any genuine sender (they won't receive a bounce message).

> So far, so good. But the MTA at elsewhere.example then goes and
> composes a non-delivery report to the envelope sender,
> victim@??? - which, courtesy of their .forward file,
> gets sent to us. Typically this non-delivery report gets a lower spam
> rating, so quite a number of them ooze in under the wire, and the
> recipients complain about being spammed with non-delivery reports.


> Anyone got useful suggestions, please?


--
He sat down and thought, in the most thoughtful way he could think. The
he fitted his paw into one of the Tracks...and then he scratched his nose
twice and stood up.
"Yes," said Winnie-the-Pooh.
"I see now," said Winnie-the-Pooh.
"I have been Foolish and Deluded," said he, "and I am a Bear of No Brain
at All."