postfix stopping spam question
i have a postfix issue that i am hoping someone can help me with. I am running postfix on my external mail server (internal is that stupid MS Exchange). Anyway, some people are receiving emails from themselves ie:
Subject: Viagr@ or whatever
<body of the message>
So my question, can postfix stop inbound spam using my internal domain name in the From line of a main header?
CATCH! we do still need to allow mail FROM my actual domain to be sent through this server.
any and all help would be GREATLY appreciated.