filter incoming messages

Posted on 2006-11-09
Last Modified: 2010-03-06
My client is receiving a rediculous amount of spam and unfortunatley they have now been blocked by Spamhaus for apparently spamming. After looking into it, it looks like the problem is down to the server sending NDR's for undeliverable incoming mail back to the spoofed email addresses on the incoming message.

I think I've configured things correctly to stop this happening but some step by step guide to confirm this would be useful.

They are running SBS2003.
Question by:barnesm6
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LVL 104

Accepted Solution

Sembee earned 250 total points
ID: 17910429
You need to filter unknown users.
Make sure that you do the tar pit as well.

Sounds like they have been blacklisted for back scatter. That is where the server accepts all email and then tries to NDR it. That is generally considered a bad idea now.

LVL 39

Expert Comment

ID: 17910436
Hi barnesm6,

Recipient filtering and tarpitting should keep you off those lists

This will stop the NDRs from going out.

As for spam, the above will stop a bit of that, but have a look at this about configuring the IMF ->

If that doesn't do it for you, then you will need 3rd party software, such as GFI or Vamsoft (both have 30 day trials)

Hope that helps,

LVL 39

Expert Comment

ID: 17910443
LVL 104

Expert Comment

ID: 17910811
Too slowing typing though....ner


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