Re: Objection to draft-ietf-6man-rfc4291bis-07.txt

Fernando Gont <fgont@si6networks.com> Thu, 02 March 2017 09:44 UTC

Return-Path: <fgont@si6networks.com>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5CAC21294BF for <ipv6@ietfa.amsl.com>; Thu, 2 Mar 2017 01:44:09 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.901
X-Spam-Level:
X-Spam-Status: No, score=-1.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_PASS=-0.001] autolearn=ham autolearn_force=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 r3bQOFX4-Q84 for <ipv6@ietfa.amsl.com>; Thu, 2 Mar 2017 01:44:07 -0800 (PST)
Received: from fgont.go6lab.si (fgont.go6lab.si [IPv6:2001:67c:27e4::14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 08E20129459 for <ipv6@ietf.org>; Thu, 2 Mar 2017 01:44:06 -0800 (PST)
Received: from [192.168.3.83] (unknown [181.165.116.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by fgont.go6lab.si (Postfix) with ESMTPSA id 9E01B8035F; Thu, 2 Mar 2017 10:44:02 +0100 (CET)
Subject: Re: Objection to draft-ietf-6man-rfc4291bis-07.txt
To: Lorenzo Colitti <lorenzo@google.com>
References: <20170223134026.GI5069@gir.theapt.org> <9277BC0B-04F3-4FC1-901E-F83A8F0E02D7@google.com> <58AF6429.70809@foobar.org> <902276E9-0521-4D4E-A42B-C45E64763896@google.com> <58AF726A.3040302@foobar.org> <F7C230DE-4759-4B78-ABF2-6799F85B3C62@google.com> <58B014F6.2040400@foobar.org> <6DA95097-8730-4353-A0C9-3EB4719EA891@google.com> <CAKD1Yr0qk_njAGnex_FZsYisCVw=eM8hXTr1v+wqvcfX_09wiQ@mail.gmail.com> <CAN-Dau0ohz3Wp55bs+eoFvSyoUjuKfjzKGSAsJS3wUt3z7TGtA@mail.gmail.com> <CAKD1Yr0wK8EiAbz39EZz-xZLtsSV2JROSzNECKtGo36Zc=RZ0Q@mail.gmail.com> <CAN-Dau2N-fv3o9o4807m_fbMktjC6hq28sMZhfECKg5cbb4g6Q@mail.gmail.com> <CAKD1Yr3tHm5x29w4L5KtKi7PqDHRxkPr6i9mJMtHLaPc2eM2GQ@mail.gmail.com> <8ce32e32-3f71-81fc-6bf5-763a4d85fed0@fundacionsadosky.org.ar> <0a3446a1-c7d2-a914-25c1-2c4cf11041b7@gmail.com> <b6432ced-1fe5-7d29-4084-37f7446d29f0@fundacionsadosky.org.ar> <c2e72e72-8e4c-b132-4d0b-2fa9e2f1df23@si6networks.com> <CAKD1Yr2Me_1Om68ONAqPxG18H21CbGD-QJZvPm1Pb-mL2ajWxw@mail.gmail.com>
From: Fernando Gont <fgont@si6networks.com>
X-Enigmail-Draft-Status: N1110
Message-ID: <9e211ff7-91df-a246-a2da-8da040ec8b28@si6networks.com>
Date: Thu, 2 Mar 2017 06:39:59 -0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0
MIME-Version: 1.0
In-Reply-To: <CAKD1Yr2Me_1Om68ONAqPxG18H21CbGD-QJZvPm1Pb-mL2ajWxw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/m0ks0zq1cvczWHuDTmb-apw8y0E>
Cc: 6man WG <ipv6@ietf.org>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Mar 2017 09:44:09 -0000

On 03/02/2017 05:57 AM, Lorenzo Colitti wrote:
> On Thu, Mar 2, 2017 at 2:15 PM, Fernando Gont <fgont@si6networks.com
> <mailto:fgont@si6networks.com>> wrote:
> 
>     among other things, it unnecessarily wastes 18 bits of entropy
> , and> 
> If you ever want that argument to be convincing you'll need to explain
> by how much the additional 18 bits of entropy benefit real users in
> realistic situations.

It's the other way around: if you are randomizing IDs for the sake of
privacy, you should make an argument for wasting 18 bits (other than "I
do it because I can").

You should also make an argument for reusing IDs in different layers and
contexts, something that is known to be a bad practice, and is the
reason for which we have had to work on: RFC7721, RFC7707, RFC7217,
RFC8064, besides patching/updating more than 14 standards.

Besides, since we (IETF) do not specify how link-layer addresses are
generated, it would be very bad to make the security/privacy properties
of the addresses we do specify (IPv6) on the properties of those
(link-layer) that we don't.

That said, if you're keen to waste 18 bits of the address, you should
probably write a draft to propose that the default subnet size/prefix be
82. Otherwise you're literally wasting 18 bits that could be used for
something else.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492