Re: comments on draft-crocker-email-arch-01

[Tony Finch <dot@xxxxxxxx>]

On Thu, 23 Dec 2004, Bruce Lilly wrote:
>
> What about the Return-Path header field?  It is explicitly defined
> as containing the content of the SMTP MAIL FROM command when an
> SMTP receiver makes "final" delivery.

Yes, and the Received: line sometimes contains a copy of the RCPT TO
command (when there's only one). These are copies of parts of the
envelope for future reference, not the envelope itself.

> I understand that there is a desire to distinguish content
> following SMTP DATA from other SMTP command content, but SMTP
> itself broke the analogy to postal mail by requiring (e-)mail
> handlers to scribble on the message content.

Analogies between the software world and the real world are usually
not perfect.

> The draft under discussion is about the overall architecture
> rather than a nitty-gritty detail peculiar to SMTP
> protocol.  From an architectural point of view it is
> important to distinguish the end-to-end, author/sender-to-
> recipient information from ancillary notations (to
> specify who/what may set/read which portions of a message),

I agree that this is necessary. However you cannot use the term "envelope"
for the transport-related header fields because "envelope" already means
something else in the context of Internet email. If you want to subdivide
the message header, please choose new terms to describe its parts.

This is an important architectural misfeature of Internet email. It is
best to talk about Internet email as it is, and not to talk about it by
shoehorning it into some idealization that doesn't apply in the real
world.

Tony.
-- 
f.a.n.finch  <dot@xxxxxxxx>  http://dotat.at/
PORTPATRICK: ON SATURDAY ALL AREAS WILL HAVE STRONG OR GALE FORCE SOUTHWEST
WINDS POSSIBLY TOUCHING SEVERE GALE FORCE AT FIRST OVER FAIR ISLE FAEROES AND
SOUTHEAST ICELAND.