Re: [ietf-smtp] EHLO domain validation requirement in RFC 5321

Sam Varshavchik <mrsam@courier-mta.com> Sun, 04 October 2020 17:31 UTC

Return-Path: <mrsam@courier-mta.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 3E6243A0925 for <ietf-smtp@ietfa.amsl.com>; Sun, 4 Oct 2020 10:31:24 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
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 BgYsu1msL-qd for <ietf-smtp@ietfa.amsl.com>; Sun, 4 Oct 2020 10:31:22 -0700 (PDT)
Received: from mailx.courier-mta.com (mailx.courier-mta.com [68.166.206.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 5D81D3A0924 for <ietf-smtp@ietf.org>; Sun, 4 Oct 2020 10:31:21 -0700 (PDT)
Received: from monster.email-scan.com (monster.email-scan.com [::ffff:192.168.0.2]) (TLS: TLSv1.3,256bits,TLS_AES_256_GCM_SHA384) by www.courier-mta.com with UTF8ESMTPS id 00000000002A0127.000000005F7A06E7.00003A39; Sun, 04 Oct 2020 13:31:18 -0400
Received: from monster.email-scan.com (localhost [127.0.0.1]) (IDENT: uid 1004) by monster.email-scan.com with UTF8SMTP id 000000000001C7C0.000000005F7A06E6.00006507; Sun, 04 Oct 2020 13:31:18 -0400
References: <20200928221602.046CE22A35B3@ary.qy> <ADA8052C-2B7D-4C50-8FFF-A3D88EC3BA58@isc.org> <ab8886ec-79b1-a89c-da38-dfe5a6e681@taugh.com> <a692482a-7777-5743-0820-894dbe7314b0@network-heretics.com> <1c1856a5-ae46-48a0-84cd-66eafb543fa9@gulbrandsen.priv.no>
Message-ID: <cone.1601832678.130598.22304.1004@monster.email-scan.com>
X-Mailer: http://www.courier-mta.org/cone/
From: Sam Varshavchik <mrsam@courier-mta.com>
To: ietf-smtp@ietf.org
Date: Sun, 04 Oct 2020 13:31:18 -0400
Mime-Version: 1.0
Content-Type: multipart/signed; boundary="=_monster.email-scan.com-22304-1601832678-0001"; micalg=pgp-sha1; protocol="application/pgp-signature"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/FA5yniZc-EFhc3AYAr7Mk4uPhg4>
Subject: Re: [ietf-smtp] EHLO domain validation requirement in RFC 5321
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: Sun, 04 Oct 2020 17:31:24 -0000

Arnt Gulbrandsen writes:

> On Sunday 4 October 2020 11:49:29 CEST, Keith Moore wrote:
>> Please cite these "well established anti-abuse metrics" because they should  
>> not be accepted as valid without question.
>
> Actually, a significant set of email senders do question and do not accept  
> them, so you're in a lot of company here, even if it may not be very good  
> company ;)
>
> But there's another aspect. Who accepts? These things are the content  
> of .procmailrc files and sieve scripts. Who has authority to accept or not  
> accept the validity of what I write in my sieve script? I believe that's a  
> local matter, out of scope for the IETF, and therefore off-topic for all  
> IETF lists.

Actually, this stuff is frequently checked during SMTP, and an undesirable  
result results in a rejected EHLO, MAIL FROM, RCPT TO, or even DATA. The  
original subject matter of this thread, the EHLO domain validation, is  
rarely done in a post-receipt phase, like in .procmailrc.

But your question is equally valid: who has the authority to accept or not  
accept the validity of how I configure my mail server with respect of the  
criteria it uses to accept or reject public E-mail? And this seems to be on  
topic, since the current document seems to require someone to accept the  
validity of certain parts of SMTP, and prohibit those bits from being used  
to determine that the E-mail is unwanted, and reject it.