Bounced Spam, faked return address, Block/Delete?

[quietas]

Here's the deal, I'm moving to Zimbra soon and need to see if it can handle this situation that my current aging (see decrepit, ancient, poo) setup can't deal with.

• Spammer sends message to X number of random names@somedomain.com
• The return address is fakename@mydomain.com
• MTA at somedomain.com sends a bound message to fakename@mydomain.com saying names@somedomain.com do not exist
• Message comes into my server at mydomain.com
• The return address fakename@domain.com does not exist and Exim complains then sends a message back
• Both servers then send messages back and forth a few time sometimes

This cycle happens a few times on some servers. I turned off bounce messages to stop it. The sender is blank with a faked return address.


This is a somewhat common situation I've been seeing over the last couple months, is this easily stopped via Zimbra?
I know the faked returns are not, but how about filtering them via the spam filter or some sort of watermarking?

[phoenix]

This is a somewhat common situation I've been seeing over the last couple months, is this easily stopped via Zimbra?
I know the faked returns are not, but how about filtering them via the spam filter or some sort of watermarking?

This is called Backscatter Spam, search the forums as there's a thread or two with details on how to stop it.