IETF Logo Mail Archive

Re: [ietf-smtp] [dispatch] Forced SMTP redirects

Viktor Dukhovni <ietf-dane@dukhovni.org> Tue, 16 March 2021 21:47 UTC

Return-Path: <ietf-dane@dukhovni.org>
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 8196B3A1075 for <ietf-smtp@ietfa.amsl.com>; Tue, 16 Mar 2021 14:47:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.199
X-Spam-Level:
X-Spam-Status: No, score=-4.199 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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 uRaE7KizybrS for <ietf-smtp@ietfa.amsl.com>; Tue, 16 Mar 2021 14:47:17 -0700 (PDT)
Received: from straasha.imrryr.org (straasha.imrryr.org [100.2.39.101]) (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 103493A0E98 for <ietf-smtp@ietf.org>; Tue, 16 Mar 2021 14:47:16 -0700 (PDT)
Received: from [192.168.1.177] (unknown [192.168.1.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by straasha.imrryr.org (Postfix) with ESMTPSA id AFF5BCF855 for <ietf-smtp@ietf.org>; Tue, 16 Mar 2021 17:47:15 -0400 (EDT)
Content-Type: text/plain; charset="us-ascii"
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\))
From: Viktor Dukhovni <ietf-dane@dukhovni.org>
In-Reply-To: <7c5c8009-6c45-a028-27c5-9ab3b94ce56a@dcrocker.net>
Date: Tue, 16 Mar 2021 19:47:14 -0200
Content-Transfer-Encoding: 7bit
Reply-To: ietf-smtp@ietf.org
Message-Id: <E4B3D416-E584-4EA8-9189-A3F7D26F16A3@dukhovni.org>
References: <CAKFo7wkawgk-Yj676kE5MqK8XuebuArMexH-eOdq_Uo7ijdimQ@mail.gmail.com> <20200710015947.0BE2D1C78A2F@ary.qy> <CAKFo7w=MJBt0FdnCcOZCXZWdkd6Jinv4TqwdpefdoaCncbZH3Q@mail.gmail.com> <6AEA7D44C8037B32BC1F3810@PSB> <81d0132b-3ebf-2b0b-756b-503bb5afdb37@dcrocker.net> <8E2D8138-EE61-486A-B957-A922F0C6F4B3@dukhovni.org> <5f803eb4-0fd1-9b15-8d3c-5c5be8ebd063@dcrocker.net> <8F833578-DFE0-4DDC-BEE2-BCA4AA1EC454@dukhovni.org> <7c5c8009-6c45-a028-27c5-9ab3b94ce56a@dcrocker.net>
To: ietf-smtp@ietf.org
X-Mailer: Apple Mail (2.3654.60.0.2.21)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/aWLXL5U3KGNgLPCuecZ028SApCc>
Subject: Re: [ietf-smtp] [dispatch] Forced SMTP redirects
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: Tue, 16 Mar 2021 21:47:19 -0000

> On Mar 16, 2021, at 6:21 PM, Dave Crocker <dhc@dcrocker.net> wrote:
> 
> Well, we have decades of operational experience.
> 
> Where is documentation that demonstrates this brittleness?

Well, I rather expect that in fact most implementations don't
actually care about the 2nd and 3rd digit that much.  In particular,
for a negative 4XX or 5XX reply is not one of the expected ones from
5321 for that command, they'll do the standard thing for a temporary
or permanent error, and if it is, it'll still be a temporary or
permanent error, be one where it may be able to log something more
precise, ...  So distinguishing between ignoring those digits and
not ignoring them should be rather difficult.


-- 
	Viktor.

v2.23.0 | Report a Bug | By Email