Re: [dmarc-ietf] I-D Action: draft-ietf-dmarc-psd-03.txt

Dotzero <> Mon, 20 May 2019 08:39 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id DF6FE120157 for <>; Mon, 20 May 2019 01:39:52 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.998
X-Spam-Status: No, score=-1.998 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id tip4e7JSRMlW for <>; Mon, 20 May 2019 01:39:51 -0700 (PDT)
Received: from ( [IPv6:2a00:1450:4864:20::32c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 012F2120154 for <>; Mon, 20 May 2019 01:39:50 -0700 (PDT)
Received: by with SMTP id t5so10720360wmh.3 for <>; Mon, 20 May 2019 01:39:50 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Q2wmgk7FOmWq/98z0jKo4ux8Y7vQQiacXmR3W6n4qaM=; b=mCpa48vj9aBOy1AZZgmdoCcjrBZ411QVLvNvHOrEkyE6og2RtMWD/Yr2uoFfZyQy0e Lo/O4Ko3ybdV1WwT0HYGtv1DYhblnKuLWEu9C5V3Kjl/xW4AhaaEh+TrK8nwDIDT+RIa QsbQjSXSjKU88ybw8SGdw+bHcxzv1fuGghZXZZOx129+rVxh3epIGz0Do95YrImEZfLS kHkLh1lGMnL8LQnOZG4xRwoz8olP8eOZG3ccXdPN/p0fsphrROfJp25UWhTTeLxyWO0U JVgi2LTuZG2RTwqnDbhk6iLRL6YVDN34yFyitk3e75DCKsCVJk+mrjMEGQxXt4ivxoT7 MZow==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Q2wmgk7FOmWq/98z0jKo4ux8Y7vQQiacXmR3W6n4qaM=; b=PNZ13ypSzpn2SedMPNEncVKFcperoa6EmryyKha5/w5TwRBtuT9SZn4J378ucoHWU6 dhlUS/h/feWV8S3TlZNgf2bw6twsOMA4kdhOj6T0dYVQSvtilZ+3xk5fOLZk8JBfgi02 syRAHbaSgljgjWTQaPcyek6rxMq/DrhEcAEu0t7WE91OFa5EaQifvb2NUSmWraVvq9sY eP4EpyMDdGXacI/qVKuZ7f/IqmfmVOupAcbP0mwuk7Alrif4DleaOfnaqpnyq3pCg2lj 8Rvmen1SKonK6t/bhbkUpiOsAiPtE9Nhbl7XrBCHQY1DMMdcjjnLmNoFpj3aif3CuP/F zDhQ==
X-Gm-Message-State: APjAAAWYyypNLSbtSrEa1z0BRbm5qCPuOtX9bqQAQhY+x5ndRvDfoQCt eoMbNqjErmIjOxM+doNeh4/DTXfAJu/YYAypnhI=
X-Google-Smtp-Source: APXvYqw1nKAcasABT9QENTVBTsNvNEWIQBCbIwtSfZTm9SSCpZozhMB7mrT3aHJeTB1UCyqkEnrOR4/3C6I9fqjmV9Y=
X-Received: by 2002:a1c:a815:: with SMTP id r21mr17130919wme.66.1558341589559; Mon, 20 May 2019 01:39:49 -0700 (PDT)
MIME-Version: 1.0
References: <> <2699063.PiBShnsfcX@l5580> <> <>
In-Reply-To: <>
From: Dotzero <>
Date: Mon, 20 May 2019 04:39:39 -0400
Message-ID: <>
To: "Murray S. Kucherawy" <>
Cc: Seth Blank <>, IETF DMARC WG <>
Content-Type: multipart/alternative; boundary="000000000000e26c2605894dac56"
Archived-At: <>
Subject: Re: [dmarc-ietf] I-D Action: draft-ietf-dmarc-psd-03.txt
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Domain-based Message Authentication, Reporting, and Compliance \(DMARC\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 20 May 2019 08:39:53 -0000

I also lean towards Seth's perspective. Additional comments in-line.

On Mon, May 20, 2019 at 1:32 AM Murray S. Kucherawy <>

> Hatless:
> On Tue, May 7, 2019 at 7:30 PM Seth Blank <> wrote:
>> 2. In Section 3.5, I'm concerned with the normative MUST NOT. This would
>> mean .example couldn't receive failure reports the way does.
>> For something like .bank or .com, this is a feature. But for a .google,
>> this is a bug. I really think this MUST NOT is, while well advised, delving
>> into policy and not interop.
> I've read Scott's replies to this as well.  The question I have is whether
> we have consensus to include this change, but that's hard to gauge when
> there's been so few names offering comments.
> I'm partial to using MUST NOT only where it goes to interoperability, so
> I'm inclined to agree with Seth.  However, I've been nudged away from that
> position on this in the past, i.e., that it can be used to encourage best
> practices and there's ample precedent for such.  Still, given other replies
> on the topic, especially the presence of "unless you know what you're
> doing" in some of the dialog, I'm wondering why this isn't a SHOULD NOT
> with an explanation of why, and in what circumstances one would deviate
> from that advice.  There are aspects of the discussion in this thread that
> would be valuable to implementers (summarized, of course).

I agree with avoiding MUST NOT in this case for the reasons given (policy
vs interoperability). I think SHOULD NOT with explanation of why might be

> I'm also inclined to agree with Seth on his points of complexity, and on
> moving contrary to DMARC's tenets.
> Having said all of that, I'm not firmly resisting given that the plan is
> to send this up as Experimental, as its deployment and results could
> usefully inform our choices with respect to standards track DMARC.
Michael Hammer