Re: [dbound] [art] [DNSOP] not DNAME, was Related Domains By DNS (RDBD) Draft

"John R Levine" <johnl@taugh.com> Thu, 28 February 2019 01:49 UTC

Return-Path: <johnl@taugh.com>
X-Original-To: dbound@ietfa.amsl.com
Delivered-To: dbound@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 6DA66130EAB for <dbound@ietfa.amsl.com>; Wed, 27 Feb 2019 17:49:01 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2
X-Spam-Level:
X-Spam-Status: No, score=-2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1536-bit key) header.d=iecc.com header.b=N15S0TK2; dkim=pass (1536-bit key) header.d=taugh.com header.b=ZwMhNuuf
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 MdywQp9xRKTa for <dbound@ietfa.amsl.com>; Wed, 27 Feb 2019 17:48:58 -0800 (PST)
Received: from gal.iecc.com (gal.iecc.com [IPv6:2001:470:1f07:1126:0:43:6f73:7461]) (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 73FF11277D2 for <dbound@ietf.org>; Wed, 27 Feb 2019 17:48:58 -0800 (PST)
Received: (qmail 67769 invoked from network); 28 Feb 2019 01:48:57 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=iecc.com; h=date:message-id:from:to:cc:subject:in-reply-to:references:mime-version:content-type:user-agent; s=108b4.5c773e09.k1902; bh=POPyT9cIKEd2L0E9MhwnBmIXJ9/y+/bJN+Fj+RAXgSc=; b=N15S0TK2MMKvcl2KBkfE+zULcv/1Px+gjzZHr/Y2ni3J1vULAPSSqbai/mZ6DlBpO1jURf/ibxgC/OcVsnq9R9TRAkzisde54IRbJsT0JV7m2sGKGXHs655cjLC5BFSK3P3FpiqK4fpHfQrGAXrZWe86pXeG/CKsgCjrYPvsn6XuOLMmic1mGOsgECRq2Hp9ApARIcsWFKx7FTogeZVGopvuPG3WKTRJRbcL/C5Fi9aQkPZU7GBNIjtkXSIDQTNp
DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=taugh.com; h=date:message-id:from:to:cc:subject:in-reply-to:references:mime-version:content-type:user-agent; s=108b4.5c773e09.k1902; bh=POPyT9cIKEd2L0E9MhwnBmIXJ9/y+/bJN+Fj+RAXgSc=; b=ZwMhNuufkK4aMWpx7+NVz1q0oJuXCqnIhMCG/QcgtCDnwSPrOMxiANYS5YZT+tWT/WUseUZ4LdsZvFZMbQkDq1dJLYLWb0CUaK6shUF6eHxmBIU+w8NKCH1mfbxP6XT5t7l5vmwf5oHtlZoLElkehcG35ZGE+o8bbKlLfuo5sNtiK2qXKFzDp5GDid6a5nxkP4Wmfm/BrYkjZHc7WngRNZrEbjYgjTnP68o+yRRRsM+dRq7pcC/ykox2YQhu4vHD
Received: from localhost ([IPv6:2001:470:1f07:1126::78:696d:6170]) by imap.iecc.com ([IPv6:2001:470:1f07:1126::78:696d:6170]) with ESMTP via TCP6; 28 Feb 2019 01:48:56 -0000
Date: 27 Feb 2019 20:48:56 -0500
Message-ID: <alpine.OSX.2.21.1902272038320.3336@ary.local>
From: "John R Levine" <johnl@taugh.com>
To: "John C Klensin" <john-ietf@jck.com>
Cc: art@ietf.org, dbound@ietf.org
In-Reply-To: <1FFA1977E97DE99C390869DA@PSB>
References: <20190227172143.10303200F57CE0@ary.local> <1FFA1977E97DE99C390869DA@PSB>
User-Agent: Alpine 2.21 (OSX 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII; format=flowed
Archived-At: <https://mailarchive.ietf.org/arch/msg/dbound/xBKczaaGfK8YN8n_-VBCb2K4myk>
Subject: Re: [dbound] [art] [DNSOP] not DNAME, was Related Domains By DNS (RDBD) Draft
X-BeenThere: dbound@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: DNS tree bounds <dbound.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dbound>, <mailto:dbound-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dbound/>
List-Post: <mailto:dbound@ietf.org>
List-Help: <mailto:dbound-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dbound>, <mailto:dbound-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 28 Feb 2019 01:49:02 -0000

On Wed, 27 Feb 2019, John C Klensin wrote:
> at least one aspect of it is probably worth mentioning.  It
> requires understanding "tree" but not any special understanding
> of IDNs, variants, etc.

You don't even have to go that for.  Let's say you do this:

foo.com. DNAME bar.org.

Then www.foo.com will be an alias for www.bar.org, but DNAMEs only affect 
names below themselves, so foo.com will remain undefined, and you can't 
put a CNAME and a DNAME on the same name.  This makes it useless for what 
most people imagine they want to use it for.

There's the additional issue that an MX with a target of a CNAME or DNAME 
doesn't work reliably, and the point you made that if you've got variants, 
you can get a very bushy tree every time a variant character appears in a 
label.

This issue has been argued at great length with proposals like BNAME and 
CLONE so let's not redo it here.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly