Many people have been asking how to block forged MAIL FROM:<> email addresses. Correct me if I wrong but it seems to me that Postfix:reject_unauthenticated_sender_login_mismatch could resolve this issue for all local addresses. If so I could see integrating this into ISPC3. You can read up on it here. It is my understanding that if used with smtpd_recipient_restrictions it will require you to be authenticated for any addresses located in $smtpd_sender_login_maps & that can be easily specified. Here is another post with a similar dilemma. http://howtoforge.com/forums/showthread.php?t=47918
