Re: [DNSOP] RFC 8482 (the ANY -> HINFO hack) and DNAME

Andrew Sullivan <ajs@anvilwalrusden.com> Sun, 17 November 2019 04:33 UTC

Return-Path: <ajs@anvilwalrusden.com>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 23972120840 for <dnsop@ietfa.amsl.com>; Sat, 16 Nov 2019 20:33:57 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-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=yitter.info header.b=SDmE8jFX; dkim=pass (1024-bit key) header.d=yitter.info header.b=CWZcIdMq
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 MM2VlTItR8wv for <dnsop@ietfa.amsl.com>; Sat, 16 Nov 2019 20:33:55 -0800 (PST)
Received: from mx4.yitter.info (mx4.yitter.info [159.203.56.111]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id C2CCA12083E for <dnsop@ietf.org>; Sat, 16 Nov 2019 20:33:55 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by mx4.yitter.info (Postfix) with ESMTP id 319DFBCE08 for <dnsop@ietf.org>; Sun, 17 Nov 2019 04:33:55 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1573965235; bh=5xhl1NtEa4L5BBGZUqKsQigx6WkFkcsevz2e2gstzxQ=; h=Date:From:To:Subject:References:In-Reply-To:From; b=SDmE8jFXLKEfPhHyNpWErgCzq5/mPAyZ0twBpLb5MCQ1+XnAOB/JoGFp+mFtUCBpP xhpMrCXnuY5kGcOBBtDMMhM/mx94idjiN7bvny/k9kyQh5yZ8WCgAHqlWw7ijQYoN7 tjyBKkqJc4EWDzVEuuyZNLfBEFf9P995D73wyr2E=
X-Virus-Scanned: Debian amavisd-new at crankycanuck.ca
Received: from mx4.yitter.info ([127.0.0.1]) by localhost (mx4.yitter.info [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ouar8vQcjopU for <dnsop@ietf.org>; Sun, 17 Nov 2019 04:33:54 +0000 (UTC)
Date: Sat, 16 Nov 2019 23:33:50 -0500
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1573965234; bh=5xhl1NtEa4L5BBGZUqKsQigx6WkFkcsevz2e2gstzxQ=; h=Date:From:To:Subject:References:In-Reply-To:From; b=CWZcIdMq65zMeOMyoy3elSqJRCKt0rreuC0jo8/FpmmQA1OGNAUU8vBKoRQ/vCM0u BwFwxjIdadSz3TSZk4ADX4MIwzfY1+LfigL4dv+5jgzLqNf2claUYP0yqq9A6Cv8mV Fge0swkMVWYPMfivU/A2d4+MvY9Xk6Am8RGisJIY=
From: Andrew Sullivan <ajs@anvilwalrusden.com>
To: dnsop@ietf.org
Message-ID: <20191117043349.lswhmnhb2d57hez5@mx4.yitter.info>
References: <6BB18D2F-4701-41CF-9B50-9EE8541ED688@dukhovni.org> <20191116144152.0AB3DF61257@ary.iecc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20191116144152.0AB3DF61257@ary.iecc.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsop/csTOhDz2fPAxJ7CFlrJmqLFOlAM>
Subject: Re: [DNSOP] RFC 8482 (the ANY -> HINFO hack) and DNAME
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 17 Nov 2019 04:33:57 -0000

On Sat, Nov 16, 2019 at 10:41:51PM +0800, John Levine wrote:
> Remember that it's invalid for an NS or MX to point to a CNAME so I assume
> it's equally invalid for them to point to a DNAME.
 
They couldn't point to a DNAME, but they could point to a target that
would resolve through a DNAME-using resolution.  To my knowledge there
is no explicit prohibition, but if you asked in the right way (such as
without DO set) you'd get a CNAME synthesized, which would mean that
the thing would break sometimes and not other times.  Seems even less
good for that reason.

Best regards,

A

-- 
Andrew Sullivan
ajs@anvilwalrusden.com