[clue-tech] spam-jacked

[David L. Anselmi]

David L. Willson wrote:
> Does anyone have an idea what to do when a spammer uses a valid email
> address, that you're responsible for, as the return address on their
> spam?  My users (and I) are getting flooded with NDRs and rejection
> messages from anti-spam systems that think we're sending things we're
> not sending.  Any ideas?

Well, these are spam too.  But messages you send have a particular 
header signature (received lines, for instance) that probably isn't 
forged well by the spammers.  So it should be easy to filter them out 
(ultimately your mailer could know all the message IDs it has sent and 
reject anything not in reply to that).  I don't know whether anyone has 
implemented such a thing.

You could also add a hard to forge header that would verify the message 
was yours and filter on that.  Similar to syn cookies, IIRC.

Dave