Re: [dmarc-ietf] ARC vs reject

Michael Thomas <mike@mtcc.com> Sat, 05 December 2020 22:07 UTC

Return-Path: <mike@fresheez.com>
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 DBC033A0DDD for <dmarc@ietfa.amsl.com>; Sat, 5 Dec 2020 14:07:16 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.651
X-Spam-Level:
X-Spam-Status: No, score=-1.651 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.249, NICE_REPLY_A=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=mtcc-com.20150623.gappssmtp.com
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 0bl4KUC__PNo for <dmarc@ietfa.amsl.com>; Sat, 5 Dec 2020 14:07:15 -0800 (PST)
Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id CA4903A0DDB for <dmarc@ietf.org>; Sat, 5 Dec 2020 14:07:15 -0800 (PST)
Received: by mail-pj1-x1034.google.com with SMTP id v1so5161102pjr.2 for <dmarc@ietf.org>; Sat, 05 Dec 2020 14:07:15 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mtcc-com.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding:content-language; bh=ZGp+5MxgVxn4ACkQyH5DKkyrx49BGbiDzYoSSYcdwUg=; b=dtQ4aHtAVRiX7T5/uZ7cS7x7/iQpDr0GS3wVk9l3Gru1Q2vsgOzEVla1+5hJjYyNii ptIcxglNe0D4HwtGvBm7FRD5fywsxHxHKSGwP+01P9kbwpJHDxruwWqiR/hUyAJrluus C3rzYGZiVtEvZDJeV4b8FTP6nCDsL73+A/XmBtqNeS8REUcPZZL7RAAKVDIiTk56LW0v YrY38l5zwLQWsmQceleP9JracUHxSVB1Q20/fsyfYkIWYULQ2JlQf6ylAT8AS6QCENkX Q6g7T5HbE4m16/4Ix1xNBCnabynlcsAQAfZ6y4x/lluYlZi9X0gd7O4fQigUbwWgl6k8 KVLQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=ZGp+5MxgVxn4ACkQyH5DKkyrx49BGbiDzYoSSYcdwUg=; b=PxHFXhYtUJnyRFfsJw9SYNMTDdmvmSKBE0DaQipImRwLRyPgrP2dn/3M3Tj9qkQciM z2BSpyofRlMk26zaQbx4TRIwNtLDDSxQKkW02xpFNeguPNLgirGZOKUtiCpOmHoRYupw 1yIzMJjXG6hZmBVl9G8e+r1UOmSYFXH5r8F6yZPnBSdvph9J6FI1JyQ+/b8KRwF8VjYa 5FWSq4xBWbTtMXmmb4aDVioRbENbMT+lxKaGzCLnx7G1t8Bkfgn+nzFpkYAW/L957/+u Xpyt3TGrsEV6GdQkV+lTMgm5TcACqb0lJeCCxEhe8lFsoBm6xFj+Z8vm78aerHUdZSV7 /UkQ==
X-Gm-Message-State: AOAM533cFaHXdRoqEXj+tuJN8lvAR8ERAEJVvUQEHU1A9xnWaHWAs03a KpeAIqvhZm03AjucfgR4zBakkf+ZXbnbD7QF
X-Google-Smtp-Source: ABdhPJyD1hS1PSzjuD22PGI5DZxXoWNzxxCDlsv8b6P7i9m0w1dPrulLTYjj++bKovyDMTgiC7QOlA==
X-Received: by 2002:a17:902:5581:b029:da:a547:b6a6 with SMTP id g1-20020a1709025581b02900daa547b6a6mr9301466pli.78.1607206034826; Sat, 05 Dec 2020 14:07:14 -0800 (PST)
Received: from mike-mac.lan (107-182-42-33.volcanocom.com. [107.182.42.33]) by smtp.gmail.com with ESMTPSA id b24sm5975882pjq.10.2020.12.05.14.07.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 05 Dec 2020 14:07:14 -0800 (PST)
To: John Levine <johnl@taugh.com>, dmarc@ietf.org
References: <20201205220233.18DCA2904B56@ary.qy>
From: Michael Thomas <mike@mtcc.com>
Message-ID: <dd59f2f3-b17e-6c2b-f756-7dcad2702fd9@mtcc.com>
Date: Sat, 5 Dec 2020 14:07:12 -0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.5.0
MIME-Version: 1.0
In-Reply-To: <20201205220233.18DCA2904B56@ary.qy>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Archived-At: <https://mailarchive.ietf.org/arch/msg/dmarc/p0yC0SWIjC4tSywYKmwg-M4ShME>
Subject: Re: [dmarc-ietf] ARC vs reject
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: Sat, 05 Dec 2020 22:07:17 -0000

On 12/5/20 2:02 PM, John Levine wrote:
> In article <c7187eca-89d2-77a7-4bd9-183eb65b7a43@mtcc.com> you write:
>>> our job to try to guess whether the bank's users are following some
>>> internal policy we can't see.
>> There is no guarantee of that. If my bank says reject that mail, I want
>> my provider to reject that mail, period. No amount of ARC shenanigans
>> should change that policy.
> OK, ARC doesn't do that. This does not mean that ARC is broken, only
> that you appear to have different policy priorities than other people.
> As you know, DMARC has never obliged recipients to follow senders'
> policies so this is nothing new.

If ARC is advocating for a bypass of p=reject that introduces a new 
state. If my policy is reject, I want you to reject the mail. If I want 
you to reject the mail unless you think it has come from an acceptable 
place with receipts, then you need a new policy tag like 
reject-except-valid-arc.

Mike