Re: [ietf-smtp] return-path vs delivered-to, was New Version Notification for draft-crocker-email-deliveredto-00.txt

[John Levine <[e-mail]>]

In article <C600B92F26F58A4D653F125D@PSB> you write:
>First of all, I think what Pete and I are both saying is that it
>is important that the specification be clear about ordering.
>That could be Return-path: on top, "Delivered-to:" on top, ...

I took a look at what qmail and postfix actually do.  I believe they
add most if not all of the Delivered-To headers found in the wild.

* If they add both headers at the same time, the Return-Path is
invariably at the top, like it says in RFC 5321.

* Both of them often add only Delivered-To when they rewrite an address or
forward mail internally. It is quite common to find Delivered-To
intermixed with other headers added along the way. See the example
below.

So here's a radical, different, new idea: let's just say Delivered-To
is a trace header. Because that's what it is.

R's,
John


== headers from a message that started on a postfix system and ended up on a qmail system ==

Return-Path: <[e-mail]>
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on gal.iecc.com
X-Spam-Level:
X-Spam-Status: No, score=-2.0 required=4.4 tests=BAYES_00,DKIM_SIGNED,
    DKIM_VALID,DKIM_VALID_AU,SPF_HELO_PASS,SPF_PASS autolearn=ham
    autolearn_force=no version=3.4.4
Delivered-To: [e-mail]
Received: (qmail 13481 invoked from network); 15 Feb 2021 20:40:01 -0000
Authentication-Results: iecc.com; spf=pass spf.mailfrom=[e-mail]
    spf.helo=eaicheck.services.net smtp.remote-ip="108.161.133.214"; dkim=pass
    header.d=eaicheck.services.net header.s=echo header.a=rsa-sha256 header.b="CRIguI7m"; dmarc=pass
    header.from=eaicheck.services.net polrec.p=reject polrec.pct=100
Received: from eaicheck.services.net (eaicheck.services.net [108.161.133.214])
  by mail1.iecc.com ([64.57.183.56])
  with ESMTP via TCP (port 29335/25) id 670487549; 15 Feb 2021 20:40:01 -0000
Received: by eaicheck.services.net (Postfix)
    id 1ADD989349; Mon, 15 Feb 2021 15:40:00 -0500 (EST)
Delivered-To: [e-mail]
Received: from eaicheck.services.net (localhost [127.0.0.1])
    by eaicheck.services.net (Postfix) with ESMTP id 05A428934C
    for <[e-mail]>; Mon, 15 Feb 2021 15:40:00 -0500 (EST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=eaicheck.services.net;
     h=to:subject:message-id:date:from; s=echo; bh=SrP2xzth3GnfaMOt7
    cSHDvAgYRXQi2Hw/QlB/TmEnQg=; b=CRIguI7msBYf+96yigHcc5v3MF37ztRxd
    aE/M+syLgyc8DxjWlRGO9dc5XhCsjry9216bTmkq+aECl3/KRW+5Dc0i1JOJ3Rw/
    Lv4q1kZl5tbanpKBrIBVFDL5fZJQxZJEwLcmmH+g6UIXy+qWLHogmbVWHTICp1EN
    dW35zH3VBi9IthzGoEr+w2Ok40lyqJqUdKElYFdas6Z9gIXnJLE3Sg7+J3j/Lo39
    MOoyub363Wj4wYdZ3BGZa3sisPgi6Tj3WkkC2SGTp3AyrbcdXkbYtUte+Yn8LIm1
    k6/Y0JTGs/kyMliL3CNzEbBK3Kb8dao6lki+zrK+pM7C1pkVSdTxQ==
Received: by eaicheck.services.net (Postfix, from userid 100)
    id F1C158934A; Mon, 15 Feb 2021 15:39:59 -0500 (EST)