Re: [dmarc-ietf] Ticket #11 (and #112) - Proposed language

Alessandro Vesely <vesely@tana.it> Thu, 17 June 2021 11:13 UTC

Return-Path: <vesely@tana.it>
X-Original-To: dmarc@ietfa.amsl.com
Delivered-To: dmarc@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E68313A1B02 for <dmarc@ietfa.amsl.com>; Thu, 17 Jun 2021 04:13:01 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.399
X-Spam-Level:
X-Spam-Status: No, score=-4.399 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1152-bit key) header.d=tana.it
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 mWvyLT8HtTP6 for <dmarc@ietfa.amsl.com>; Thu, 17 Jun 2021 04:12:57 -0700 (PDT)
Received: from wmail.tana.it (wmail.tana.it [62.94.243.226]) (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 6DB8F3A1B75 for <dmarc@ietf.org>; Thu, 17 Jun 2021 04:12:51 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tana.it; s=delta; t=1623928365; bh=WV44Xj19AAS0Bg1cHa7NmyUFj0Im7n6p6uOtwe2FXg0=; l=968; h=To:References:From:Date:In-Reply-To; b=BTRnPu/tvl6VASUWhoEYeNSZRRbOGaLNcD6YtPkgPgi/V2hvXAkD8RcSuEpmi+QmL wp5NzFuUCHwvL4q7AFACfWS7Nsx1hbu3abxSQchEuSbJBV2vntqAtjHMNuaLSPQfUF 3S9mqKkCgsoHYo8qSEy792QuqfuRubsofLM8M7stGEf4OJlYjj5pF2IyoedQA
Authentication-Results: tana.it; auth=pass (details omitted)
Original-From: Alessandro Vesely <vesely@tana.it>
Received: from [172.25.197.111] (pcale.tana [172.25.197.111]) (AUTH: CRAM-MD5 uXDGrn@SYT0/k, TLS: TLS1.3, 128bits, ECDHE_RSA_AES_128_GCM_SHA256) by wmail.tana.it with ESMTPSA id 00000000005DC03D.0000000060CB2E2C.00003C69; Thu, 17 Jun 2021 13:12:44 +0200
To: John Levine <johnl@taugh.com>, dmarc@ietf.org
References: <20210616180222.53DC311FBCDC@ary.qy>
From: Alessandro Vesely <vesely@tana.it>
Message-ID: <6e76e4af-e592-0103-33dc-4cda6b129071@tana.it>
Date: Thu, 17 Jun 2021 13:12:44 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0
MIME-Version: 1.0
In-Reply-To: <20210616180222.53DC311FBCDC@ary.qy>
Content-Type: text/plain; charset="us-ascii"; format="flowed"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/dmarc/HxdtMlUkmgmJRJ_qF3jmBXGoLig>
Subject: Re: [dmarc-ietf] Ticket #11 (and #112) - Proposed language
X-BeenThere: dmarc@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Domain-based Message Authentication, Reporting, and Compliance \(DMARC\)" <dmarc.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dmarc>, <mailto:dmarc-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dmarc/>
List-Post: <mailto:dmarc@ietf.org>
List-Help: <mailto:dmarc-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dmarc>, <mailto:dmarc-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 17 Jun 2021 11:13:02 -0000

On Wed 16/Jun/2021 20:02:21 +0200 John Levine wrote:
> Let's close ticket #112 and stop.


I agree that the definition given in the PSD is clear enough:

    For DMARC purposes, a non-existent domain is a domain for which there
    is an NXDOMAIN or NODATA response for A, AAAA, and MX records.  This
    is a broader definition than that in [RFC8020].

However, by that definition a domain with a Null MX [RFC7505] is an existent 
domain for DMARC purposes.  Perhaps this apparent contradiction could be noted 
by adding a sentence somewhere, for example:

    Even though the bare existence of a domain does not entail that it can send
    or receive email, the presence or absence of the relevant DNS RRs determines
    which policy between sp= and np= is applicable.  If a DMARC record is found
    for a domain that would be non-existent by the above definition, the p=
    policy defined there is still the one to be applied.

Would that add clarity?


Best
Ale
--