[DNSOP] Using the SOA in a NXDOMAIN response (Was: [internet-drafts@ietf.org: I-D Action: draft-bortzmeyer-dnsop-nxdomain-cut-00.txt]

Stephane Bortzmeyer <bortzmeyer@nic.fr> Fri, 13 November 2015 19:53 UTC

Return-Path: <bortzmeyer@nic.fr>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D829F1B2B9F for <dnsop@ietfa.amsl.com>; Fri, 13 Nov 2015 11:53:08 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.3
X-Spam-Level:
X-Spam-Status: No, score=-1.3 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, J_CHICKENPOX_37=0.6] autolearn=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 xjUF9AuiWseu for <dnsop@ietfa.amsl.com>; Fri, 13 Nov 2015 11:53:08 -0800 (PST)
Received: from mail.bortzmeyer.org (aetius.bortzmeyer.org [IPv6:2001:4b98:dc0:41:216:3eff:fece:1902]) (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 0B1661B2B93 for <dnsop@ietf.org>; Fri, 13 Nov 2015 11:53:08 -0800 (PST)
Received: by mail.bortzmeyer.org (Postfix, from userid 10) id A85DD3BBC5; Fri, 13 Nov 2015 20:53:06 +0100 (CET)
Received: by mail.sources.org (Postfix, from userid 1000) id 75DDF1907E4; Fri, 13 Nov 2015 20:50:15 +0100 (CET)
Date: Fri, 13 Nov 2015 20:50:15 +0100
From: Stephane Bortzmeyer <bortzmeyer@nic.fr>
To: "Wessels, Duane" <dwessels@verisign.com>
Message-ID: <20151113195015.GB32106@sources.org>
References: <20151106082238.GA2307@nic.fr> <A62EC834-C954-446C-9F7A-AB6D1F955C7F@verisign.com> <20151112081514.GA16017@laperouse.bortzmeyer.org> <39D878B4-9239-4983-8083-36BCA365BE62@verisign.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <39D878B4-9239-4983-8083-36BCA365BE62@verisign.com>
X-Transport: UUCP rules
X-Operating-System: Debian GNU/Linux 8.2
X-Charlie: Je suis Charlie
User-Agent: Mutt/1.5.23 (2014-03-12)
Archived-At: <http://mailarchive.ietf.org/arch/msg/dnsop/T5KiP3dQZa9GZCJa9d5WYaYORvk>
Cc: "dnsop@ietf.org" <dnsop@ietf.org>
Subject: [DNSOP] Using the SOA in a NXDOMAIN response (Was: [internet-drafts@ietf.org: I-D Action: draft-bortzmeyer-dnsop-nxdomain-cut-00.txt]
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.15
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: Fri, 13 Nov 2015 19:53:09 -0000

On Thu, Nov 12, 2015 at 06:13:04PM +0000,
 Wessels, Duane <dwessels@verisign.com> wrote 
 a message of 57 lines which said:

> As Mark pointed out, we can't use the SOA to make NXDOMAIN more aggressive.
> 
> For a name like foo.bar.example.com and an NXDOMAIN response from
> example.com we can't assume that there would be a zone cut between
> foo and bar.

Could anyone explain in detail why is it so? [I don't understand why
the zone cut is important here: using the SOA does not depend on
whether there is a zone cut or not.]

Let's say I query foo.bar.example to example's name servers. I get:

...
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 64182
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 8, ADDITIONAL: 1
...
;; QUESTION SECTION:
;foo.bar.example.		IN SOA
...

example.			5400 IN	SOA nsmaster.nic.example. hostmaster.nic.example. (
				2222956935 ; serial
				3600       ; refresh (1 hour)
                                ....

It can mean only one thing, that bar.example does not exist. How could
it be different?