IETF Logo Mail Archive

Re: [ietf-smtp] mailing lists are complicated, was Email explained from first principles

John R Levine <johnl@taugh.com> Sat, 29 May 2021 14:23 UTC

Return-Path: <johnl@taugh.com>
X-Original-To: ietf-smtp@ietfa.amsl.com
Delivered-To: ietf-smtp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 17F8C3A11D7 for <ietf-smtp@ietfa.amsl.com>; Sat, 29 May 2021 07:23:33 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.1
X-Spam-Level:
X-Spam-Status: No, score=-2.1 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=iecc.com header.b=BJwuVR+W; dkim=pass (2048-bit key) header.d=taugh.com header.b=BNWXheBQ
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rwoqV84U9Cj2 for <ietf-smtp@ietfa.amsl.com>; Sat, 29 May 2021 07:23:27 -0700 (PDT)
Received: from gal.iecc.com (gal.iecc.com [IPv6:2001:470:1f07:1126:0:43:6f73:7461]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 740473A11D5 for <ietf-smtp@ietf.org>; Sat, 29 May 2021 07:23:27 -0700 (PDT)
Received: (qmail 67514 invoked from network); 29 May 2021 14:23:24 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=iecc.com; h=date:message-id:from:to:subject:in-reply-to:references:mime-version:content-type; s=107b7.60b24e5c.k2105; bh=QkZq3qCg4onXuRBXb/zT8Pm1EP5maK8zRLkA9IGCVHE=; b=BJwuVR+Wzd9lWoVrTD+Xj6ByNXAYFKaeLxbQNt6Cbc/PSKuG8Gue2hkMRNcpJiQTUG+XMd92inXzcbg4efFqplqpqNtdBJFSbjH8g/PeMpECWm9RiQWUtdlMXjTyc9nPwIHzZSVbqMSqC32/znhFO1kiEE7YLiSDzc4gKXp+ohbP13vRH6uCzq8cMJMyjyjC2xb3H5+6WPLSuC3YpEuOqk1EyCuobcQQm580G6zFJDb+iYdtuNPb2cJeoWW1mRi8FEIZY6Ws8R453zYX3mFpmyxSLh2eHP5F/UzM8VRrQ8WtmBhFQtcWFCbGRnVRBjT/eC1rH7cMzEHgapjmyltBeA==
DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=taugh.com; h=date:message-id:from:to:subject:in-reply-to:references:mime-version:content-type; s=107b7.60b24e5c.k2105; bh=QkZq3qCg4onXuRBXb/zT8Pm1EP5maK8zRLkA9IGCVHE=; b=BNWXheBQ90hB3ftvJrL4XNctkogEPZfrCekZq5he2eFaci+blURYrOn+XvFHV0D1FLtGXUJZayd74WY/PrRbVvO4FpZs3RxJVZDoxV0ZXf2xKIgwagON3O3iupDyv5xY/zmqwEN/1ge6Q+LdXGrPBLL09JzdLSh9ZQdHVOXq66415Fipgw3eTIGeiHPwZyCtLrTasV/9CcLRsM6gIrliNPhPcWDVJlHinswYeesXLLZMvBG4obypLl928sQ70uVGQ/bGWHgsDTpA/DLB5rz4VBQGf9ZZHGgWrRLasiAWe9Kizt4m7BT/LmNf/odnxXwO8mwtD/2XNhYmfCb1rcP7Sg==
Received: from ary.qy ([IPv6:2001:470:1f07:1126::78:696d:6170]) by imap.iecc.com ([IPv6:2001:470:1f07:1126::78:696d:6170]) with ESMTPS (TLS1.2 ECDHE-RSA AES-256-GCM AEAD) via TCP6; 29 May 2021 14:23:24 -0000
Received: by ary.qy (Postfix, from userid 501) id 58B3D8ED811; Sat, 29 May 2021 10:23:22 -0400 (EDT)
Received: from localhost (localhost [127.0.0.1]) by ary.qy (Postfix) with ESMTP id E14BC8ED7F1; Sat, 29 May 2021 10:23:22 -0400 (EDT)
Date: Sat, 29 May 2021 10:23:22 -0400
Message-ID: <b6936b7c-2898-e013-4ffe-af52bc1efedd@taugh.com>
From: John R Levine <johnl@taugh.com>
To: Alessandro Vesely <vesely@tana.it>, ietf-smtp@ietf.org
X-X-Sender: johnl@ary.qy
In-Reply-To: <d60c6034-bab1-2346-394d-e41312a46222@tana.it>
References: <20210528181821.943B08E0563@ary.qy> <d60c6034-bab1-2346-394d-e41312a46222@tana.it>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"; format="flowed"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/8pguADmeWBFaT6a6Bqb18Z9JuBo>
Subject: Re: [ietf-smtp] mailing lists are complicated, was Email explained from first principles
X-BeenThere: ietf-smtp@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Discussion of issues related to Simple Mail Transfer Protocol \(SMTP\) \[RFC 821, RFC 2821, RFC 5321\]" <ietf-smtp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ietf-smtp>, <mailto:ietf-smtp-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ietf-smtp/>
List-Post: <mailto:ietf-smtp@ietf.org>
List-Help: <mailto:ietf-smtp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ietf-smtp>, <mailto:ietf-smtp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 29 May 2021 14:23:33 -0000

On Sat, 29 May 2021, Alessandro Vesely wrote:
> ARC is a completely different thing.  It introduces a third party, the 
> sender, which modifies the message header in such a way to induce receivers 
> to accept a message even if it fails DMARC.  Semantically, it is very similar 
> to Dave's Use of the Sender Header Field.

Ho, it is really nothing like that.  It provides log info to so that the 
final recipient can retroactively do filtering that the intermediate hosts 
didn't.  It is true that you do have to know which intermediate hosts 
might plausibly do that, but small systems rarely get ARC'ed mail from 
more than a handful of places.

> I see no conflict between these two methods.

Just wondering, but has anyone implemented the mutant DKIM you are 
proposing?  Is there a spec or an I-D?

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly

v2.23.0 | Report a Bug | By Email