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:

From: tom@abc.com
To: tom@abc.com
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.