Re: DMARC: perspectives from a listadmin of large open-source lists
John C Klensin <john-ietf@jck.com> Mon, 14 April 2014 09:15 UTC
Return-Path: <john-ietf@jck.com>
X-Original-To: ietf@ietfa.amsl.com
Delivered-To: ietf@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C8AE51A0297 for <ietf@ietfa.amsl.com>; Mon, 14 Apr 2014 02:15:00 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.973
X-Spam-Level:
X-Spam-Status: No, score=-0.973 tagged_above=-999 required=5 tests=[BAYES_40=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RP_MATCHES_RCVD=-0.272] autolearn=ham
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 s4aJteSvzQG4 for <ietf@ietfa.amsl.com>; Mon, 14 Apr 2014 02:14:56 -0700 (PDT)
Received: from bsa2.jck.com (bsa2.jck.com [70.88.254.51]) by ietfa.amsl.com (Postfix) with ESMTP id 5F2171A0106 for <ietf@ietf.org>; Mon, 14 Apr 2014 02:14:56 -0700 (PDT)
Received: from [198.252.137.115] (helo=JcK-HP8200.jck.com) by bsa2.jck.com with esmtp (Exim 4.82 (FreeBSD)) (envelope-from <john-ietf@jck.com>) id 1WZcyb-0004Y1-I6; Mon, 14 Apr 2014 05:14:53 -0400
Date: Mon, 14 Apr 2014 05:14:48 -0400
From: John C Klensin <john-ietf@jck.com>
To: Doug Barton <dougb@dougbarton.us>, ietf@ietf.org
Subject: Re: DMARC: perspectives from a listadmin of large open-source lists
Message-ID: <6C80882F19CCEDFE15E987CA@JcK-HP8200.jck.com>
In-Reply-To: <534B9760.90301@dougbarton.us>
References: <20140414024956.26078.qmail@joyce.lan> <534B524F.4050206@dcrocker.net> <alpine.BSF.2.00.1404132327560.26258@joyce.lan> <E0B7196CB2603B80BBEC21AF@JcK-HP8200.jck.com> <alpine.BSF.2.00.1404132346420.26386@joyce.lan> <1EBDF5239EEE5202D3837D25@JcK-HP8200.jck.com> <534B9760.90301@dougbarton.us>
X-Mailer: Mulberry/4.0.8 (Win32)
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
X-SA-Exim-Connect-IP: 198.252.137.115
X-SA-Exim-Mail-From: john-ietf@jck.com
X-SA-Exim-Scanned: No (on bsa2.jck.com); SAEximRunCond expanded to false
Archived-At: http://mailarchive.ietf.org/arch/msg/ietf/3IqG9zOjQdk36tgzakCUyDqnjiE
X-BeenThere: ietf@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: IETF-Discussion <ietf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ietf>, <mailto:ietf-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/ietf/>
List-Post: <mailto:ietf@ietf.org>
List-Help: <mailto:ietf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ietf>, <mailto:ietf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 14 Apr 2014 09:15:01 -0000
--On Monday, April 14, 2014 01:08 -0700 Doug Barton <dougb@dougbarton.us> wrote: >> But this takes us back to Ned's point (or at least my >> interpretation of it): it is lots easier to fix a bad DMARC >> config, ignore restrictive DMARC specifications, or even to >> abandon DMARC entirely, than it is to believe that we can >> upgrade every MTA and MUA on the network to start accepting >> percent hacks, bang paths, or the syntax characters used to >> denote them, again. Or any other strange local-part syntax >> anyone is likely to come up with, e.g., perhaps we could use >> plus signs, hyphens, or appropriately-escaped backslashes. Or >> we could steal "/" and "=" back from X.400 gateways. Right. > > Well + is out, since that's used by various local filtering > solutions. Doug, I think you are missing my, and probably John Levine's, attempts at humor. Let me spell it out: The point was the "+" is used in local filtering and, perhaps more generally, as subaddresses with all sorts of applications. Both "%" and "!", along with <@a:x@y>, were, at different points and gateways to different systems, mail routing mechanisms that are now sufficiently deprecated and/or rare that many intermediate MTAs will singly reject or drop messages containing them. "/" and "=" were used on the local part of addresses bound for, or coming from, X.400 gateways and many systems will reject (or possibly) drop messages with local parts in which they appear but that don't conform to that gateway syntax... except that "/" may also designate delivery to a file and "//" may be a piece of ancient JCL. It isn't just the MTAs: Some POP and IMAP client MUAs will trash this stuff too. As with the MTAs, using these sorts of trick conventions without disrupting the existing mail systems, including those that don't pay any attention to DMARC or DKIM headers and hence are unaffected by the problem, requires that everything be upgraded and upgraded more or less on a flag day basis. There is a strong rule in RFC 5321 and its predecessor forbidding anything but the final delivery system from rewriting a local-part and it is there precisely because one doesn't know what sorts of conventions and indicates were begin used there. The bottom line is that trying to work around this by a trick syntax convention is really hard, unlikely to succeed, and quite likely to result in legitimate messages disappearing and/or breaking existing conforming systems. > But your point is well taken ... the "right" answer may be to > fix or discard DMARC, I honestly don't know. But in a world > where DMARC is here to stay, or if not DMARC then some other > anti-spam solution that breaks mailing list forwarding; and in > that same world where mailing list traffic is negligible (and > therefore the cost of breaking mailing lists is in the noise > compared to the benefits of deploying said anti-spam solution) > it's incumbent on the mailing list software folks to solve > this problem. I'm going to risk more humor and suggest that everyone who believes that mailing list traffic is negligible and the cost of breaking them is in the noise should be immediately unsubscribed from all IETF-related lists, including this one. best, john
- Re: DMARC: perspectives from a listadmin of large… John R Levine
- Re: DMARC: perspectives from a listadmin of large… Sabahattin Gucukoglu
- Re: DMARC: perspectives from a listadmin of large… Scott Kitterman
- Re: DMARC: perspectives from a listadmin of large… Brian E Carpenter
- Re: DMARC: perspectives from a listadmin of large… John R Levine
- Re: DMARC: perspectives from a listadmin of large… Sabahattin Gucukoglu
- Re: DMARC: perspectives from a listadmin of large… Dave Crocker
- DMARC: perspectives from a listadmin of large ope… Robin H. Johnson
- Re: DMARC: perspectives from a listadmin of large… Robin H. Johnson
- Re: DMARC: perspectives from a listadmin of large… Robin H. Johnson
- Re: DMARC: perspectives from a listadmin of large… ned+ietf
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: DMARC: perspectives from a listadmin of large… John R Levine
- RE: DMARC: perspectives from a listadmin of large… Alex Ojeda
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: DMARC: perspectives from a listadmin of large… John Levine
- Re: DMARC: perspectives from a listadmin of large… Alessandro Vesely
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… John Levine
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… ned+ietf
- Re: DMARC: perspectives from a listadmin of large… Dave Crocker
- Re: DMARC: perspectives from a listadmin of large… John R Levine
- Re: DMARC: perspectives from a listadmin of large… John C Klensin
- Re: DMARC: perspectives from a listadmin of large… John R Levine
- Re: DMARC: perspectives from a listadmin of large… Sabahattin Gucukoglu
- Re: DMARC: perspectives from a listadmin of large… John C Klensin
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… John C Klensin
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- RE: DMARC: perspectives from a listadmin of large… l.wood
- Re: DMARC: perspectives from a listadmin of large… Dave Crocker
- Re: DMARC: perspectives from a listadmin of large… John C Klensin
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- RE: DMARC: perspectives from a listadmin of large… MH Michael Hammer (5304)
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Mailman 2.1.16 [DMARC: perspectives from a listad… Brian E Carpenter
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Theodore Ts'o
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Dave Cridland
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- Re: protecting the Internet from DMARC damage, wa… John Levine
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… John Levine
- Re: DMARC: perspectives from a listadmin of large… Dave Cridland
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… John Levine
- RE: DMARC: perspectives from a listadmin of large… MH Michael Hammer (5304)
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… Dave Crocker
- Re: DMARC: perspectives from a listadmin of large… Murray S. Kucherawy
- RE: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: DMARC: perspectives from a listadmin of large… Douglas Otis
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… John Levine
- RE: protecting the Internet from DMARC damage, wa… MH Michael Hammer (5304)
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Brian E Carpenter
- RE: protecting the Internet from DMARC damage, wa… John R Levine
- Re: DMARC: perspectives from a listadmin of large… Doug Barton
- Re: DMARC: perspectives from a listadmin of large… Scott Kitterman
- Re: DMARC: perspectives from a listadmin of large… Scott Kitterman
- Re: protecting the Internet from DMARC damage, wa… Murray S. Kucherawy
- Re: DMARC: perspectives from a listadmin of large… Dave Cridland
- Re: DMARC: perspectives from a listadmin of large… Alessandro Vesely
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Michael Richardson
- Re: DMARC: perspectives from a listadmin of large… ned+ietf
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Theodore Ts'o
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… John R Levine
- Re: DMARC: perspectives from a listadmin of large… Dave Crocker
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Michael Richardson
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Theodore Ts'o
- Re: DMARC: perspectives from a listadmin of large… S Moonesamy
- Re: DMARC: perspectives from a listadmin of large… Pete Resnick
- Re: Mailman 2.1.16 [DMARC: perspectives from a li… Brian E Carpenter
- RE: DMARC: perspectives from a listadmin of large… MH Michael Hammer (5304)
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… Hector Santos
- Re: DMARC: perspectives from a listadmin of large… Brian E Carpenter
- Re: DMARC: perspectives from a listadmin of large… Theodore Ts'o
- Re: DMARC: perspectives from a listadmin of large… Sabahattin Gucukoglu
- Re: DMARC: perspectives from a listadmin of large… Scott Kitterman
- Re: DMARC: perspectives from a listadmin of large… Theodore Ts'o
- Let's talk (was: DMARC: perspectives from a lista… S Moonesamy
- (DMARC) Why mailing lists are only sort of special John R Levine
- RE: Let's talk (was: DMARC: perspectives from a l… MH Michael Hammer (5304)
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… John R. Levine
- Re: DMARC: perspectives from a listadmin of large… Pete Resnick
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: DMARC: perspectives from a listadmin of large… Michael Richardson
- Re: DMARC: perspectives from a listadmin of large… John Levine
- RE: Let's talk (was: DMARC: perspectives from a l… S Moonesamy
- Re: Let's talk (was: DMARC: perspectives from a l… Dave Cridland
- Re: (DMARC) Why mailing lists are only sort of sp… Murray S. Kucherawy
- Re: (DMARC) Why mailing lists are only sort of sp… Dave Cridland
- Re: (DMARC) Why mailing lists are only sort of sp… Dave Cridland
- RE: Let's talk (was: DMARC: perspectives from a l… MH Michael Hammer (5304)
- Re: (DMARC) Why mailing lists are only sort of sp… John R Levine
- Re: (DMARC) Why mailing lists are only sort of sp… Murray S. Kucherawy
- Re: (DMARC) Why mailing lists are only sort of sp… Murray S. Kucherawy
- Re: (DMARC) Why mailing lists are only sort of sp… Miles Fidelman
- Re: (DMARC) Why mailing lists are only sort of sp… Pete Resnick
- Re: (DMARC) Why mailing lists are only sort of sp… tytso
- Re: DMARC: perspectives from a listadmin of large… Miles Fidelman
- Re: (DMARC) Why mailing lists are only sort of sp… Mark Andrews
- Re: (DMARC) We've been here before, was Why maili… John R Levine
- Re: (DMARC) How a whitelist would work, was Why m… John R Levine
- Re: (DMARC) We've been here before, was Why maili… Pete Resnick
- Re: (DMARC) Why mailing lists are only sort of sp… Dave Cridland
- Re: (DMARC) Why mailing lists are only sort of sp… Yoav Nir
- Re: (DMARC) We've been here before, was Why maili… John R Levine
- Re: (DMARC) Why mailing lists are only sort of sp… Martin Rex
- Re: (DMARC) Why mailing lists are only sort of sp… Yoav Nir
- Re: (DMARC) Why mailing lists are only sort of sp… Dave Cridland
- RE: (DMARC) Why mailing lists are only sort of sp… MH Michael Hammer (5304)
- Re: (DMARC) We've been here before, was Why maili… Pete Resnick
- Re: (DMARC) Why mailing lists are only sort of sp… Miles Fidelman
- Re: (DMARC) We've been here before, was Why maili… ned+ietf
- Re: (DMARC) We've been here before, was Why maili… Miles Fidelman
- Re: (DMARC) We've been here before, was Why maili… Martin Rex
- Re: (DMARC) We've been here before, was Why maili… ned+ietf
- Re: (DMARC) We've been here before, was Why maili… Douglas Otis
- Re: (DMARC) We've been here before, was Why maili… Martin Rex
- Re: (DMARC) We've been here before, was Why maili… John Levine
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… John Levine
- Re: (DMARC) We've been here before, was Why maili… Martin Rex
- Re: (DMARC) We've been here before, was Why maili… John Levine
- Re: (DMARC) We've been here before, was Why maili… Michael Richardson
- Re: (DMARC) How a whitelist would work, was Why m… Michael Richardson
- Re: (DMARC) Why mailing lists are only sort of sp… Michael Richardson
- Re: (DMARC) How a whitelist would work, was Why m… John R Levine
- Re: (DMARC) How a whitelist would work, was Why m… Miles Fidelman
- Re: (DMARC) Why mailing lists are only sort of sp… John Levine
- Re: (DMARC) We've been here before, was Why maili… John Levine
- Re: (DMARC) How a whitelist would work, was Why m… Yoav Nir
- Re: (DMARC) How a whitelist would work, was Why m… John R Levine
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… John R Levine
- Re: (DMARC) We've been here before, was Why maili… Theodore Ts'o
- Re: (DMARC) We've been here before, was Why maili… Douglas Otis
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… John R Levine
- Re: (DMARC) We've been here before, was Why maili… Theodore Ts'o
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… tytso
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… tytso
- Re: (DMARC) We've been here before, was Why maili… Brian E Carpenter
- Re: (DMARC) We've been here before, was Why maili… Murray S. Kucherawy
- Re: (DMARC) We've been here before, was Why maili… Theodore Ts'o
- [off-off-track] Re: (DMARC) We've been here befor… Miles Fidelman
- Re: (DMARC) We've been here before, was Why maili… John Levine
- Re: (DMARC) We've been here before, was Why maili… Alessandro Vesely