[Mailman-Users] [Mailman-Developers] Sender field

[Stephen J. Turnbull]

>>>>> "Brad" == Brad Knowles <brad at stop.mail-abuse.org> writes:

At 7:50 PM -0400 2006-04-28, Barry Warsaw wrote:

    >> Whatever else we decide, I don't agree, or at least, it won't
    >> help us.  $3.6.6 says that Resent-* headers are to be added by
    >> a user.  It also says that these are purely informational
    >> headers, so I don't see how adding them will instruct a
    >> receiving MTA usefully.

Sender doesn't instruct *conformant* MTAs at all, does it?  AFAIK the
only thing that a RFC 2821-conforming MTA looks at is the Return-Path
header, and it's supposed to remove that.

So this is purely a matter of pragmatic self-defense against broken
MTAs that do bounce to Sender.

    Brad> 	Siunce the RFC doesn't specifically talk about "relay
    Brad> agents" as separate from "users", I think we could argue
    Brad> that Mailman would qualify as a "user" in this context.
    Brad> Therefore, the Resent-* headers seem to be most appropriate.

Agreed.  For a number of reasons, I think this information can be
useful.  As I mentioned elsewhere, the Resent-Message-Id field can be
used to supply a UUID that we can trust (eg, for constructing
canonical archive URLs).  Unlike the Received headers, these are
readable by humans who aren't wall-eyed, helpful in tracing delays,
for example.

    Brad> If we need something that will be noticed by other MTAs
    Brad> beyond the envelope sender and the "Return-Path:" &
    Brad> "Errors-To:" headers, then we're going to have to carefully
    Brad> think about this.

What's an Errors-To header?  I can't find it in the usual suspects.

But I don't see any particular need for thought.  Conforming Internet
MTAs don't look at message headers, period.

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