backscatter problem {Scanned by Allteks Mailsafe}

[Paul Houselander (SME)]

>Hi all,  anyone help with some good rules to combat backscatter email?
i seem to have a real problem with this at the moment, mostly bouncing
back from .ru domains to my customers.  i'm sure a ruleset will help but
i'm not certain what would >be best, header checks or something in the
spam rules?
>
>thanks
>
>SMJ  

>>The solutions depends on your MTA, if you are using sendmail check this:
>>
>>http://elqui.dcsc.utfsm.cl/util/email/backscatter.html
>>
>>And this:
>>
>>http://www.spamcop.net/fom-serve/cache/329.html
>>
>>If you are using postfix check this:
>>
>>http://www.postfix.org/BACKSCATTER_README.html
>>
>>If you have another MTA just google "mta+backscatter" and you'll find
>>tons of information.

I think most of the suggestions are to use something like milter-ahead to
reject invalid users, however since the beginning of the week ive been
seeing more and more backscatter targeted at valid aliases in which case
recipient verification will not make any difference.

I spent a while yesterday looking at the watermark feature of mailscanner,
if your customers send their outbound e-mail via a server you control it
works a treat.

Only problem I can see is it seems to incorrectly flag, read receipts and
some out of office replies (which I think has been discussed quite a bit on
this list) but I personally think it's a small price to pay for a clean
inbox!

An alternative that I was using was I use mimedefang as while as
mailscanner, I wrote a mimedefang filter to reject all bounces for certain
domains that were being targeted, not really a great ideal as I understand
it breaks certain RFC's but was the only way I could control mail flow on my
servers.

Good Luck

Paul