You probably want to check this
http://slett.net/spam-filtering-for-mx/exim-bounces.html
This very well explains how to limit bounces to real users. After all,
there is no reason accepting a bounce if you didn't send a message.
Although I prefer doing a discard on the bounce than denying it. It may
well consume more bandwidth, but you won't get listed at
rfc-ignorant.org for refusing bounces.
> Subject:
> [exim] Filtering spam bounces
> From:
> Alastair Campbell <ac@???>
> Date:
> Sun, 14 May 2006 22:02:05 +0100
> To:
> exim-users@???
>
> To:
> exim-users@???
>
>
> Hi,
>
> If I'm asking the wrong question in the wrong place, please do point me
> somewhere else - I'm new here.
>
> The problem:
> I am receiving a lot of bounces from someone using my domain as the
> reply to address. Not thousands a day (like 4 days last year), but
> roughly 30 a day for about a month now, all to random strings of letters
> @alastc.com. (e.g. wfhwdb@???.), from different IP addresses
> around the world.
>
> The solution concept:
> I would like to have a rule somewhere that says "If email subject
> matches ('failure notice' | 'Undelivered' | 'Returned mail') and is not
> addressed to a specific (known) email address, dump it."
>
> The question:
> My setup is exim with spamassassin (and clamav) on top of Debian (root
> access), but where abouts would I specify something like that?
>
> There are three other notable factors:
>
> 1. I don't want to dump the catch-all email, I quite often use things
> like 'amazon@...' so I know if my address gets passed on.
>
> 2. I don't want spamassassin to learn from the bounces, as I don't want
> to miss legitimate bounces.
>
> 3. I'm not a sys admin, by any stretch of the imagination. Debian makes
> it pretty easy to set up and maintain the email system, but I won't be
> re-compiling anything ;)
>
> Thanks in advance for any pointers,
>
> -Alastair
>