[Mimedefang] Spam through trusted mx relay

[David Koski]

I was wondering if anyone had any thoughts if there is a better way to deal
with spam through a trusted mx and forwarded to my local mail server.

In a University environment we have several different domains that get
forwarded to our local mail servers.  Since the relay/mx information, etc is
a trusted known source of mail the only thing I've been able to do is tag it
as spam with SpamAssassin despite the rest of the header and the originating
information is clearly spam.

Unfortunately, while some of the forwarding MX systems are protected, they
aren't protected as well as I would prefer them to be.  

Anyone have some thoughts on a better way to detect this type of forwarded
spam and just out right reject just plain bad email from a known good
source?

	David