Re: [v6ops] When Android might disconnect because lack of DHCPv6 (was: Implementation Status of PREF64)

Alexandre Petrescu <alexandre.petrescu@gmail.com> Sat, 16 October 2021 19:54 UTC

Return-Path: <alexandre.petrescu@gmail.com>
X-Original-To: v6ops@ietfa.amsl.com
Delivered-To: v6ops@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id F3E033A0AE8; Sat, 16 Oct 2021 12:54:53 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 0.667
X-Spam-Level:
X-Spam-Status: No, score=0.667 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_ADSP_CUSTOM_MED=0.001, FORGED_GMAIL_RCVD=1, FREEMAIL_FROM=0.001, NICE_REPLY_A=-0.001, NML_ADSP_CUSTOM_MED=0.9, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665, URIBL_BLOCKED=0.001] autolearn=no 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 iUV2C1yI3sMF; Sat, 16 Oct 2021 12:54:49 -0700 (PDT)
Received: from oxalide-smtp-out.extra.cea.fr (oxalide-smtp-out.extra.cea.fr [132.168.224.13]) (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 51E403A0AE7; Sat, 16 Oct 2021 12:54:49 -0700 (PDT)
Received: from pisaure.intra.cea.fr (pisaure.intra.cea.fr [132.166.88.21]) by oxalide-sys.extra.cea.fr (8.14.7/8.14.7/CEAnet-Internet-out-4.0) with ESMTP id 19GJskIc006502; Sat, 16 Oct 2021 21:54:46 +0200
Received: from pisaure.intra.cea.fr (localhost [127.0.0.1]) by localhost (Postfix) with SMTP id 437D2200CCD; Sat, 16 Oct 2021 21:54:46 +0200 (CEST)
Received: from muguet1-smtp-out.intra.cea.fr (muguet1-smtp-out.intra.cea.fr [132.166.192.12]) by pisaure.intra.cea.fr (Postfix) with ESMTP id 3334B200C3D; Sat, 16 Oct 2021 21:54:46 +0200 (CEST)
Received: from [10.14.0.58] ([10.14.0.58]) by muguet1-sys.intra.cea.fr (8.14.7/8.14.7/CEAnet-Internet-out-4.0) with ESMTP id 19GJsj3D031645; Sat, 16 Oct 2021 21:54:45 +0200
To: David Farmer <farmer@umn.edu>, Owen DeLong <owen=40delong.com@dmarc.ietf.org>
Cc: V6 Ops List <v6ops@ietf.org>
References: <DDA36020-90CC-471B-83AD-3D98950F1164@delong.com> <702CB018-1A02-4B32-B9AA-7C7B31521F12@delong.com> <CAKD1Yr0jZR8Efzr_Y6FeiBvHYS8ATmDupx2ABTXXy-rSA_QjmA@mail.gmail.com> <1adb70a8-db0a-4ea6-f721-c1035343cda3@foobar.org> <DM6PR02MB69249D4F0A8003E77EC9F153C3B19@DM6PR02MB6924.namprd02.prod.outlook.com> <E1FED93B-674C-46DD-8C39-F6C30475C48A@delong.com> <CAKD1Yr34jv_N0jGKdg=sG76oGU7PdRjYFC_-w9Uvzs=7oGm38w@mail.gmail.com> <E6316781-AC7D-438F-B216-75B1DF9217DC@delong.com> <CAKD1Yr10OKMJ1y8bs5xpt6jS8ZWsqs66oFCXmp-QLySS5Yn4hg@mail.gmail.com> <CAN-Dau3JxPucFnbwZB-M5UD3KkSV++7u03AMQ7vOZJKqPHpJ3Q@mail.gmail.com> <403087B1-51A5-4DF4-9884-441D443DACC2@delong.com> <CAN-Dau3FBLVUSTQsFTrbDEAdy95L8evPdeD_Jg1sK34+DK0O1A@mail.gmail.com> <2D83CE75-368B-4DFD-A7B2-8E0DE8C4D733@delong.com> <01036fb1-6de2-58c8-ae1e-ff9d90385685@gmail.com> <A930BCD4-6EB0-4DE5-AF75-D2ADE347A102@delong.com> <CAN-Dau2WOAzX0gDR8053edg++tC8W_rmMH9x_Z-gBhFhd5p9Bw@mail.gmail.com>
From: Alexandre Petrescu <alexandre.petrescu@gmail.com>
Message-ID: <80209480-706d-8a11-f79f-1e59d78e329d@gmail.com>
Date: Sat, 16 Oct 2021 21:54:45 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <CAN-Dau2WOAzX0gDR8053edg++tC8W_rmMH9x_Z-gBhFhd5p9Bw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: fr
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/xq88rUIaNCKDiMEykiTSeEbE5rk>
Subject: Re: [v6ops] When Android might disconnect because lack of DHCPv6 (was: Implementation Status of PREF64)
X-BeenThere: v6ops@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <v6ops.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/v6ops>, <mailto:v6ops-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/v6ops/>
List-Post: <mailto:v6ops@ietf.org>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/v6ops>, <mailto:v6ops-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 16 Oct 2021 19:54:54 -0000


Le 12/10/2021 à 19:24, David Farmer a écrit :
> 
> On Tue, Oct 12, 2021 at 12:00 PM Owen DeLong 
> <owen=40delong.com@dmarc.ietf.org 
> <mailto:40delong.com@dmarc.ietf.org>> wrote:
> 
>> My ISP CPE offers both IPv4 and IPv6; for IPv6 it offers either
> SLAAC or
>> DHCPv6 but not simultaneously.
> 
> I’m not sure how this is possible.
> 
> The data necessary for SLAAC is in the RA that includes the M bit to
>  tell the host to go ask the DHCPv6 server for an address, so how 
> would your CPE prevent the android from doing SLAAC without 
> authorization?
> 
> Does it really implement the necessary NAC-like behavior to block the
> SLAAC address from the android or are you just guessing here?
> 
> Owen
> 
> 
> I think the CPE will only set either the A-flag or M-flag but not 
> both at the same time in the RA and only start up the DHCPv6 process 
> if the M-flag is set.
> 
> However, most CPE I know the Flags are independent, you can set one 
> or the other or both.
> 
> Some, don't let you turn off the A-flag to turn off SLAAC. My 
> XFINITY(Comcast) Gateway is that way, you can only configure DHCPv6 
> off or on, SLAAC is always on. Probably so you can accidentally
> break IPv6 for Android.

A version of Free ISP CPE that I have is also in a similar situation: if
DHCPv6 is on then M is set and A reset; I guess that by specificationn
it is possible to have both M and A set.

I suspect people dont set both M and A in RA because of conflicts that
might appear in parameters of Hosts.

Alex

> 
> Thanks
> 
> -- =============================================== David Farmer 
> Email:farmer@umn.edu <mailto:Email%3Afarmer@umn.edu> Networking & 
> Telecommunication Services Office of Information Technology 
> University of Minnesota 2218 University Ave SE        Phone: 
> 612-626-0815 Minneapolis, MN 55414-3029   Cell: 612-812-9952 
> ===============================================