IETF Logo Mail Archive

RE: There are claims of ambiguity over what is a link-local address

Christian Huitema <huitema@microsoft.com> Mon, 07 May 2012 16:55 UTC

Return-Path: <huitema@microsoft.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 DD89B21F846E for <ipv6@ietfa.amsl.com>; Mon, 7 May 2012 09:55:12 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.749
X-Spam-Level:
X-Spam-Status: No, score=-3.749 tagged_above=-999 required=5 tests=[AWL=-0.150, BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XiwRSEKFDfnz for <ipv6@ietfa.amsl.com>; Mon, 7 May 2012 09:55:11 -0700 (PDT)
Received: from am1outboundpool.messaging.microsoft.com (am1ehsobe001.messaging.microsoft.com [213.199.154.204]) by ietfa.amsl.com (Postfix) with ESMTP id E1E1621F8458 for <ipv6@ietf.org>; Mon, 7 May 2012 09:55:07 -0700 (PDT)
Received: from mail82-am1-R.bigfish.com (10.3.201.229) by AM1EHSOBE004.bigfish.com (10.3.204.24) with Microsoft SMTP Server id 14.1.225.23; Mon, 7 May 2012 16:54:54 +0000
Received: from mail82-am1 (localhost [127.0.0.1]) by mail82-am1-R.bigfish.com (Postfix) with ESMTP id 9990E4A0407 for <ipv6@ietf.org>; Mon, 7 May 2012 16:54:53 +0000 (UTC)
X-SpamScore: 0
X-BigFish: VS0(zzzz1202hzzz2fh2a8h668h839h944hd25h)
X-Forefront-Antispam-Report: CIP:131.107.125.8; KIP:(null); UIP:(null); IPV:NLI; H:TK5EX14HUBC102.redmond.corp.microsoft.com; RD:none; EFVD:NLI
Received-SPF: pass (mail82-am1: domain of microsoft.com designates 131.107.125.8 as permitted sender) client-ip=131.107.125.8; envelope-from=huitema@microsoft.com; helo=TK5EX14HUBC102.redmond.corp.microsoft.com ; icrosoft.com ;
Received: from mail82-am1 (localhost.localdomain [127.0.0.1]) by mail82-am1 (MessageSwitch) id 1336409691712905_16947; Mon, 7 May 2012 16:54:51 +0000 (UTC)
Received: from AM1EHSMHS007.bigfish.com (unknown [10.3.201.252]) by mail82-am1.bigfish.com (Postfix) with ESMTP id A9BFB460115 for <ipv6@ietf.org>; Mon, 7 May 2012 16:54:51 +0000 (UTC)
Received: from TK5EX14HUBC102.redmond.corp.microsoft.com (131.107.125.8) by AM1EHSMHS007.bigfish.com (10.3.207.107) with Microsoft SMTP Server (TLS) id 14.1.225.23; Mon, 7 May 2012 16:54:51 +0000
Received: from TK5EX14MBXC272.redmond.corp.microsoft.com ([169.254.2.64]) by TK5EX14HUBC102.redmond.corp.microsoft.com ([157.54.7.154]) with mapi id 14.02.0298.005; Mon, 7 May 2012 16:54:49 +0000
From: Christian Huitema <huitema@microsoft.com>
To: Dave Thaler <dthaler@microsoft.com>, "ipv6@ietf.org" <ipv6@ietf.org>
Subject: RE: There are claims of ambiguity over what is a link-local address
Thread-Topic: There are claims of ambiguity over what is a link-local address
Thread-Index: AQHNK/QfH0wm9HiMeUyuYY0AjTdiAZa95UMAgAAO+4CAAILfgIAAEu8g
Date: Mon, 07 May 2012 16:54:48 +0000
Message-ID: <C91E67751B1EFF41B857DE2FE1F68ABA0BC26723@tk5ex14mbxc272.redmond.corp.microsoft.com>
References: <20120506235919.66E7B206E4F1@drugs.dv.isc.org> <4FA77236.30109@gmail.com> <4FA77EC7.6000406@gmail.com> <9B57C850BB53634CACEC56EF4853FF653B5B6560@TK5EX14MBXW605.wingroup.windeploy.ntdev.microsoft.com>
In-Reply-To: <9B57C850BB53634CACEC56EF4853FF653B5B6560@TK5EX14MBXW605.wingroup.windeploy.ntdev.microsoft.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [157.54.51.74]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: microsoft.com
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.12
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: <http://www.ietf.org/mail-archive/web/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: Mon, 07 May 2012 16:55:13 -0000

>> Link-Local Unicast Addresses          1111 1110 10   1/1024
>> Site-Local Unicast Addresses          1111 1110 11   1/1024
>...
> So they define the /10 as the link local *prefix*, within which any *addresses* have to fall into the /64.
> The rest of the /10 is unused but is still defined as link-local scope.

The specs may be reasonable, but they did cause confusion for addresses in FE80::/10 but out of FE80::/64. Some implementations appear to treat these addresses as global, others as local, and yet others as "unexpected." There may be a way to use these addresses as an attack vectors against poor implementations. Given that, I would suggest to be very specific:

* FE80::/64 is used for configuring link local addresses;
* FE80::/10 is reserved by the IETF. 
* By default, implementations SHOULD discard packets received from addresses in FE80::/10 outside of FE80::/64

-- Christian Huitema

v2.23.0 | Report a Bug | By Email