Wietse, >>How would Postfix know out that mail is forwarded from OSU Microsoft exchange >>servers? Postfix only receives all outbound emails from 8 exchange hub servers. The email received by Postfix is probably 1) osu.edu account to non-osu.edu account; 2) osu.edu account to osu.edu forwarding account which is non-osu.edu email address; 3) non-osu.edu account to osu.edu forwarding account which is non-osu.edu address.
>>Is it mail with a non-OSU envelope sender from a system inside OSU? Not really. For example. Somebody from his/her yahoo account sends an mail to my osu.edu email which is forwarded to my Hotmail account. >>Must it also have a non-OSU envelope recipient? >From postfix logs, recipient address must be a non-OSU envelope recipient. >>If the rule is complex, then I recommend using an external content filter. >>Amavisd-new supports policies that trigger on all kinds of message >>properties. Postfix just an MTA. When I sent the mail to ask, I feel our rule is a little complicated. Can't Postfix header_checks perform too complicated rules? Amavisd-new maybe another big change to us, but this is option. Thanks, Carl -----Original Message----- From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of Wietse Venema Sent: Tuesday, July 29, 2014 11:33 AM To: Postfix users Subject: Re: Can Postfix automatically add line "Resent-From: <email address>" in the header? Xie, Wei: > Greetings, > > Our OSU State University uses Microsoft exchange servers as our main > email system. Many users' email accounts are forwarding accounts, > which forward emails of nam...@osu.edu<mailto:nam...@osu.edu> > (i. e. smith.8...@osu.edu<mailto:smith.8...@osu.edu>) to other email > systems such as gmail, yahoo, Hotmail, Buckeyemail, etc. > Before these outbound emails are leaving from Ohio state university, > they are scanned by our Security DLP (Data Loss Protection) servers on > which MTA Postfix is running. > > Here we have a question about postfix. When the message passes by > Postfix, can Postfix automatically add line "Resent-From: <OSU email > address>" in the header? How would Postfix know out that mail is forwarded from OSU Microsoft exchange servers? Is it mail with a non-OSU envelope sender from a system inside OSU? Must it also have a non-OSU envelope recipient? If the rule is complex, then I recommend using an external content filter. Amavisd-new supports policies that trigger on all kinds of message properties. Postfix just an MTA. Wietse
