Re: [dmarc-ietf] Spirit of RFC8601 section 5 for invalid A-R headers

Damian Lukowski <rfc@arcsin.de> Fri, 03 April 2020 20:53 UTC

Return-Path: <rfc@arcsin.de>
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 D07313A0AB3 for <dmarc@ietfa.amsl.com>; Fri, 3 Apr 2020 13:53:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.099
X-Spam-Level:
X-Spam-Status: No, score=-2.099 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_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=arcsin.de
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 ScqHwASSAHtN for <dmarc@ietfa.amsl.com>; Fri, 3 Apr 2020 13:53:17 -0700 (PDT)
Received: from scalar.arcsin.de (scalar.arcsin.de [185.162.250.16]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id C1F643A0AAD for <dmarc@ietf.org>; Fri, 3 Apr 2020 13:53:16 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=arcsin.de; h= content-transfer-encoding:content-language:content-type :content-type:in-reply-to:mime-version:date:date:message-id:from :from:references:subject:subject:x-amavis-category; s=dkim01; t= 1585947194; x=1587761595; bh=Ri3mykdd2xiN0Ix+1U+S2fyva4eLyaX0D5+ P/AG8gpw=; b=gnbJgRy6Lzl6rZZAs+bFfPYuxHNH4ItTiQI0waynqYyVOnA4XBI fjPTU6YoBgoBdmHKDeNje8LBei6LdfLTRL7QJbEA3XlRRW40avgiOuV8l3IdOlVa dMwmyaMPvRWXUTnzAHLcx5jab7zd+b1Yn85wh5reFOONPWEl96KbuGsM=
X-Amavis-Category: scalar.arcsin.de; category=CleanTag
To: dmarc@ietf.org
References: <20200403200526.DDAD616FC9A3@ary.qy>
From: Damian Lukowski <rfc@arcsin.de>
Message-ID: <cbda91cc-ef04-84d6-e6af-4f69c24a368b@arcsin.de>
Date: Fri, 3 Apr 2020 22:53:57 +0200
MIME-Version: 1.0
In-Reply-To: <20200403200526.DDAD616FC9A3@ary.qy>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/dmarc/VX6EqH639d_pImdWDSiwG4Myz1E>
Subject: Re: [dmarc-ietf] Spirit of RFC8601 section 5 for invalid A-R headers
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: Fri, 03 Apr 2020 20:53:19 -0000

> Honestly, it doesn't matter.  The only A-R headers you can trust are
> the ones that your own system added, and the point of that text is
> that you should delete ones that look like yours but that you didn't
> add.

How can a MUST not matter? My personal interest in this area is what
needs to be done according to the specification, which unfortunately
uses a metaphoric verb for the condition of the MUST.