From: owner-ietf-smtp(_at_)mail(_dot_)imc(_dot_)org [mailto:owner-ietf-
smtp(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of Hector Santos
Sent: Monday, May 17, 2010 7:14 PM
Subject: Edited Mail and Resent Headers
I am trying to determine if Resent Headers, in particular the
Resent-Message-ID applies in cases the original message content is
altered (i.e, a user corrected his online message) and the mail is
re-introduced into the mail stream.
What are you thoughts about this?
I don't know exactly what you mean by "applies" here.
Here's my read on it:
Section 3.6.6 of RFC5322 says the use of any Resent-*: header field is a
SHOULD. That language isn't strong enough to say that a re-mailer of some
kind, whether or not it alters the content, that doesn't also add a
Resent-Message-ID: field is in violation of that RFC.
Even Section 3.6.4, which defines Message-ID:, doesn't specifically say that an
altered form MUST receive a new Message-ID:. It's clear that this is the
intent, but there's nothing normative about it, so a remailer that doesn't
issue a new Message-ID: is also not in violation of that RFC.
So since the language is soft, I'd say it always applies, but an agent that
chooses not to follow that text isn't actually violating anything.
On the flipside, an agent that re-sends a message that has (or hasn't) been
altered is free to decide whether or not to add a Resent-Message-Id field, so
its presence (or absence) doesn't tell you definitively whether or not there's
been an alteration enroute.