Re: [Exim] String expansion in filters

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Author: David Woodhouse
Date:  
To: Doug Jolley
CC: exim-users
Subject: Re: [Exim] String expansion in filters
On Sat, 2004-04-10 at 10:08 -0700, Doug Jolley wrote:
> >If you want to do this kind of thing, then do it with a 'fakereject' at
> >ACL time. The SMTP error will cause a spammer to silently drop the mail
> >and move on to the next victim, while a _legitimate_ mail will trigger a
> >bounce to be generated by the MTA which was trying to deliver it to you.
>
> Thanks to you and the other responders for your thoughtful input/help.
>
> Your point is well taken. I CERTAINLY don't want to contribute to the
> problem. However, I don't see how your suggested alternative
> accomplishes my objective of communicating a procedure back to the
> _legitimate_ sender for delivery completion.


The machine attempting to deliver mail on behalf of a _legitimate_
sender will generate a bounce. The bounce will, if the machine in
question isn't behaving particularly stupidly, include your explanatory
text.

On the other hand, if it's a spammer or a virus sending the offending
message then they _won't_ generate a bounce; they'll just move on to the
next victim.

Try sending me a message without a Message-Id: header for an example of
how this works. You can see the DATA ACL which does this at
http://www.infradead.org/~dwmw2/eximconf/include/acl-content

> Also, I would appreciate your thoughts on TMDA (Tagged Message Delivery Agent -
> http://www.tmda.net).


Nah; this is a family list.

I don't think I've actually come up against TMDA, but if I did I
wouldn't bother to deal with it -- especially if I'd been trying to help
you when I sent you the email which triggered it.

--
dwmw2