Re: [dbound] [DNSOP] Over on the dbound list: draft-dcrocker-dns-perimeter-00

Dave Crocker <dhc@dcrocker.net> Thu, 04 April 2019 14:54 UTC

Return-Path: <dhc@dcrocker.net>
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 8077B1200FF for <dbound@ietfa.amsl.com>; Thu, 4 Apr 2019 07:54:23 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Level:
X-Spam-Status: No, score=-2.7 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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=dcrocker.net
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 MLaz_OSD8TUK for <dbound@ietfa.amsl.com>; Thu, 4 Apr 2019 07:54:22 -0700 (PDT)
Received: from simon.songbird.com (simon.songbird.com [72.52.113.5]) (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 E69601200EC for <dbound@ietf.org>; Thu, 4 Apr 2019 07:54:21 -0700 (PDT)
Received: from [192.168.1.85] (108-226-162-63.lightspeed.sntcca.sbcglobal.net [108.226.162.63]) (authenticated bits=0) by simon.songbird.com (8.14.4/8.14.4/Debian-4.1ubuntu1.1) with ESMTP id x34Eu5EM002344 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for <dbound@ietf.org>; Thu, 4 Apr 2019 07:56:05 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=dcrocker.net; s=default; t=1554389765; bh=+kNz+P0C1MrvmQOO8xPGPdxJISE1Alykh74rz/XS5oM=; h=Subject:To:References:Reply-To:From:Date:In-Reply-To:From; b=YtW+GjxVrrgFHQP2kgWq3w5pf1ChsNki2s8mYqq11emqJAhNaS7gHPnRdQ9ao9Yeh IKucCjH34aOL//UiOYHVYy0QjRUyckI97Wo4UtzLMJ8PVuDHRV73x35mI/hjZibtJt 53QOePtERfGIXbqOvFWhsT/ZSzPv6Eyv2OA1MNvM=
To: dbound@ietf.org
References: <03202426-5fa7-de6a-688d-491bde7402a8@dcrocker.net> <CA+nkc8BL2ArJNxWE8QdRf_76Wvt_85fZmzV92diN7qENXP6jvg@mail.gmail.com>
Reply-To: dcrocker@bbiw.net
From: Dave Crocker <dhc@dcrocker.net>
Organization: Brandenburg InternetWorking
Message-ID: <17bd278f-17b4-7b77-f209-253a290cfde7@dcrocker.net>
Date: Thu, 4 Apr 2019 07:54:14 -0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1
MIME-Version: 1.0
In-Reply-To: <CA+nkc8BL2ArJNxWE8QdRf_76Wvt_85fZmzV92diN7qENXP6jvg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/dbound/tyGd4c2vpUVLjdiAPsy1X2blyk0>
Subject: Re: [dbound] [DNSOP] Over on the dbound list: draft-dcrocker-dns-perimeter-00
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, 04 Apr 2019 14:54:24 -0000

Bob,

On 4/4/2019 7:17 AM, Bob Harold wrote:
> I have two questions:
> 
> If I want to separate these levels:
> example.
> a.example.
> b.a.example.
> 
> Then a.example is both a 'begin' and 'end' node.  Do I put in two 
> records,  one for 'begin' and one for 'end'?

First, note that Perimeters are actually /between/ node names.  So the 
above would be:

 > example.
   {perimeter}
 > a.example.
   {perimeter}
 > b.a.example.

Some choices for marking these will depend upon the specific Schema that 
is defined.  So, for example, I could imagine a Schema that demands an 
'end' above a 'begin' and I could imagine a Scheme that merely requires 
either one to be in place, or requires a specific one.

So for a simple hierarchy there might a schema specification might 
merely mandate that each perimeter down a hierarchy be marked by a new 
'begin':


   {perimeter}

 > example.
   \
    ._perim TXT begin <schema>

   {perimeter}

 > a.example.
   \
    ._perim TXT begin <schema>


   {perimeter}

 > b.a.example.
   \
    ._perim TXT begin <schema>


Each _perim record, in the above sequence, for example., is declaring 
that there is a Perimeter above the associated DNS node name.

but yes, the requirement might be for more verbosity:


   {perimeter}

 > example.
   \
    ._perim TXT begin <schema>
    ._perim TXT end <schema>

   {perimeter}

 > a.example.
   \
    ._perim TXT end <schema>
    ._perim TXT begin <schema>


   {perimeter}

 > b.a.example.
   \
    ._perim TXT end <schema>
    ._perim TXT begin <schema>

And my having to write this response makes me suspect there's some 
benefit in adding an end-begin shorthand to the specification, to reduce 
the verbosity and permit a single record to declares Perimeters both 
above and below the node.  It's purpose would be for Perimeter hierarchy 
have a one-name level, such as your example (and I suspect would be a 
common use.)


> Secondly, if I have:
> a.example.
> b.a.example.
> c.a.example.
> d.a.example.
> ...
> z.a.example.
> 
> And I want to separate z.a.example, but not the others, and there are 
> often changes to the list.  Without having to mark every one, how can I 
> (as a.example), mark above the cut that z.a.example is separate?

Cool.  Subset of branches.

 > a.example.
 > b.a.example.
 > c.a.example.
 > d.a.example.
 > ...
 > z.a.example.
   \
    ._perim TXT begin <schema>

would clearly work.

If there were a need to instead have a.example make the declaration, I 
don't see an obvious answer.

My first thought is for the Scheme to have a sub-notation, to indicate 
that the presence of the Perimeter is not for all branches, such as by 
having it list the children links it applies to.  But that's not feeling 
terribly satisfactory.

d/

-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net