Re: [ietf-smtp] New Version Notification for draft-crocker-email-deliveredto-00.txt

[Pete Resnick <[e-mail]>]

On 4 Feb 2021, at 17:46, John Levine wrote:

> In article <[e-mail]> you 
> write:
>> This draft was prompted by discussion in the emailcore wg, but is
>> outside the scope of the wg charter.  So the spec is being pursued as
>> AD-sponsored.
>
> This short draft fills in a long standing gap in the specs.  MTAs have 
> been
> adding Delivered-To headers for over 20 years but the header has never 
> been
> registered with IANA and there's never been a spec saying what it 
> does.

Documenting an existing header field is always a good thing, but a 
couple of questions:

Is there any functional or semantic difference between an MDA adding 
Delivered-To: and an MDA adding a Received: with a 'for' clause 
containing the same address? Is it somehow conveying the semantic 
difference between an MTA and an MDA? It seems like Received: could have 
been used, and it can carry more info. (And perhaps the right question 
to ask before all that is: Why did folks start adding a Delivered-To: 
instead of just adding a Received: field with a 'for' clause?)

Also, does adding the Return-Path: happen before or after adding the 
Delivered-To:? The spec seems to indicate before, but it doesn't mention 
Return-Path: at all.

pr
-- 
Pete Resnick https://www.episteme.net/
All connections to the world are tenuous at best