Re: RFC7084

Sander Steffann <> Mon, 09 December 2013 21:56 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 5DED11AE108 for <>; Mon, 9 Dec 2013 13:56:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: 0.194
X-Spam-Status: No, score=0.194 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_EQ_NL=0.55, HOST_EQ_NL=1.545, SPF_PASS=-0.001] autolearn=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id Ks0eWz7GRn-h for <>; Mon, 9 Dec 2013 13:56:26 -0800 (PST)
Received: from ( []) by (Postfix) with ESMTP id 613431AE0D0 for <>; Mon, 9 Dec 2013 13:56:26 -0800 (PST)
Received: from localhost (localhost []) by (Postfix) with ESMTP id D32544D; Mon, 9 Dec 2013 22:56:19 +0100 (CET)
X-Virus-Scanned: Debian amavisd-new at
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id fd+THQ7bgn7h; Mon, 9 Dec 2013 22:56:18 +0100 (CET)
Received: from ( []) by (Postfix) with ESMTPSA id B3A7A34; Mon, 9 Dec 2013 22:56:17 +0100 (CET)
Content-Type: text/plain; charset="windows-1252"
Mime-Version: 1.0 (Mac OS X Mail 7.0 \(1822\))
Subject: Re: RFC7084
From: Sander Steffann <>
In-Reply-To: <>
Date: Mon, 09 Dec 2013 22:56:16 +0100
Content-Transfer-Encoding: quoted-printable
Message-Id: <>
References: <>
To: Wuyts Carl <>
X-Mailer: Apple Mail (2.1822)
Cc: "<>" <>
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 09 Dec 2013 21:56:28 -0000

Hi Carl,

> Not sure I should sent this one to DHCPv6 WG or the global IETF v6, so feel free to forward it if needed.
> Last week, RFC7084 got posted.  I did already post a message on a rather badly phrased req (a SHOULD one regarding “long-enough”, but bumped into the next one today (this one being a lot worse!!).
> “”
> WAA-6:   If the IPv6 CE router receives a Router Advertisement
>             message (described in [RFC4861]) with the M flag set to 1,
>             the IPv6 CE router MUST do DHCPv6 address assignment
>             (request an IA_NA option).
> “”
> I’m not sure who came up with this one, but this is really a no-go.
> So, according to this req, the DHCPv6 client must request an ia_na option if an M=1 is being received on his link ???  I might have understood it all wrong, but as far as I know, M=1 is not linked directly to ia_na, ia_pd is enough on its own, no ??

Actually the other way around: M=1 is linked to ia_na but not to ia_pd. A CPE always does ia_pd, regardless of the M flag, but the ia_na is only requested when M=1.

>  So, the CPE is expected to change its DHCPv6 client configuration based upon receiving an RA with this M=1 content ?

Yep, that's the meaning :-)

> I’m very curious on the replies now, but this seems really be going the wrong way.  You can launch a CPE which either listen to RA or not, and bound accordingly, however, listen + bind + force ia_na looks a bit too much to me.

You always have to listen to RA, otherwise you won't have your default gateway. If you don't want a global address on the CPE WAN link (assuming that A=0 in the prefix option, but it doesn't have to be) you could ignore the M=1 flag and not do ia_na.