I have a question concerning mail forwarding:
When does the Message-ID: of a mail change?
I assume a new Message-ID: is generated as soon as a mail is beeing sent. Thus, when I forward a mail it gets a new Message-ID:. Now I stumbled over a little problem. I found a hosting service which offers automatic mail forwarding (e.g. from email@example.com to firstname.lastname@example.org). But forwarded messages keep their original Message-ID. Thus the forwarded mail actually "looks" like beeing sent from the originating address. Only hint for forwarding are new or different headerlines. The From:, Return-Path: and Message-ID: remain the same. I know, for From: and Return-Path:, this is RFC compliant (well, it should be ;). But does this count for the Message-ID: as well? Does it have to remain the same when forwarding, maybe in order to make the mail trackable similar to usenet systems, or does the Message-ID: has to change, as soon as the mail gets send again, even when forwarding?
I hope you got what I wanted to ask. My head is aching pretty much, I'm on this issue since about 6 1/2 hours now and pretty fed up.
With best regards,