Re: [dhcwg] [EXTERNAL] [v6ops] Re: Question to DHCPv6 Relay Implementors regarding draft-ietf-dhc-dhcpv6-pd-relay-requirements

Bob Hinden <bob.hinden@gmail.com> Wed, 14 October 2020 22:27 UTC

Return-Path: <bob.hinden@gmail.com>
X-Original-To: dhcwg@ietfa.amsl.com
Delivered-To: dhcwg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5C5843A10E5; Wed, 14 Oct 2020 15:27:43 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.098
X-Spam-Level:
X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
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 JVphk2qLcWUS; Wed, 14 Oct 2020 15:27:41 -0700 (PDT)
Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 3BF343A10E2; Wed, 14 Oct 2020 15:27:41 -0700 (PDT)
Received: by mail-wr1-x42f.google.com with SMTP id i1so880470wro.1; Wed, 14 Oct 2020 15:27:41 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=lqFgFRDT6xSvoWW5//+X1zYpO3f7rb4jO6wl5iLQanM=; b=UrJjgZsPShSGSYvWif069dofJbjl7/hHJsv3Uq+h+1xBAAQ0zErOPNcQHRUI2CkkSt MpfeLp6gu1Fp2f1WVccBORDSv8wHv8gaCn37AdzwhxNrWCaAYLywY26Bk7TBbDHvBWyG KX8jEb+A6C+lssmDfm/jflZnAvYcAAU12Ho+/7QBF3Hnyqf7u3z0mzIuPI4S1z6a7bP7 GARPXXqMsTfQsZHQ/hw1QSd/sTY1v527gC0/wUsFIUUMCrA6W0Z1mUeokw8WNPOvttTb cRR5fZE66+Oh/aZZNEpVmNefUG/9TfEApFKRL5mys3XmEW9WzKYscTvRprsdMsEp3jkz Sw8A==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=lqFgFRDT6xSvoWW5//+X1zYpO3f7rb4jO6wl5iLQanM=; b=OdQMvyCgcs3Pb41yluEcLnc+GxJE0lR4zy/J52fD45JmssVyGvl1gV9T8bnVdJQQIo IzaPqge8sRKbE7gyF2tX0gE9ZCgQOrLB7MUCJXiC7sCz+ysMulTRMhQSntnmdR1Gc+wU 2WyQWg2pPW077Wbf+tFiDUcJ5yGDo0yfb7V+0hftmi572aKAoPDxPUkUKcUxJoISeyiU q7D4EaIl7dFlf9IhjYpdJC2T0MrfcbhvLxKNv1MC7xaa3fTa/g5DSZNzaHBQFHBH9y/E wTB1D0totMVH6aBVSdYSvkN2AFQSccKjpVnRUCjq+GcArkSSDjgo9FAxm1tGA1z41Zpx IO3Q==
X-Gm-Message-State: AOAM531MCHDLrPMC5JGe0CGihEEUDdQxbsraey34mfvI6ihcWpyaTArX PlRMWoAcfVY9m4P1SJl7aS4=
X-Google-Smtp-Source: ABdhPJzHwxgqzUIpy4oH6P1G9q2Ti0pb5YeM4mnwIIQC39s2KntnHtpPOFD6qEu/yzNCMeZFtAkETg==
X-Received: by 2002:a5d:4b49:: with SMTP id w9mr928368wrs.41.1602714459219; Wed, 14 Oct 2020 15:27:39 -0700 (PDT)
Received: from ?IPv6:2601:647:5a00:ef0b:d1a9:870b:80a8:51e3? ([2601:647:5a00:ef0b:d1a9:870b:80a8:51e3]) by smtp.gmail.com with ESMTPSA id q5sm1153500wrs.54.2020.10.14.15.27.36 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Oct 2020 15:27:38 -0700 (PDT)
From: Bob Hinden <bob.hinden@gmail.com>
Message-Id: <C0083F20-230A-42BE-9E3B-4CFB6A8ABF96@gmail.com>
Content-Type: multipart/signed; boundary="Apple-Mail=_556C11A0-C932-4D1E-A909-9C384A46CB33"; protocol="application/pgp-signature"; micalg=pgp-sha512
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.17\))
Date: Wed, 14 Oct 2020 15:27:34 -0700
In-Reply-To: <0284272facf5494f81eff3e49597a246@boeing.com>
Cc: Bob Hinden <bob.hinden@gmail.com>, Michael Richardson <mcr+ietf@sandelman.ca>, dhcwg <dhcwg@ietf.org>, IPv6 List <ipv6@ietf.org>, v6ops list <v6ops@ietf.org>
To: "Templin (US), Fred L" <Fred.L.Templin@boeing.com>
References: <5f119ffbb67245a9b9d34a0d8f7398f4@boeing.com> <10487.1602608586@localhost> <378d3420690246bbae253fb15be8c9a7@boeing.com> <19627.1602701863@localhost> <1b34b9bec59e4a00af8b9d8f182d23ff@boeing.com> <BD2B4938-B362-40A7-BCF7-DDA270A64BF7@gmail.com> <0284272facf5494f81eff3e49597a246@boeing.com>
X-Mailer: Apple Mail (2.3445.104.17)
Archived-At: <https://mailarchive.ietf.org/arch/msg/dhcwg/XendgqY_2N2Ap8DZBsvg4eHRdI0>
Subject: Re: [dhcwg] [EXTERNAL] [v6ops] Re: Question to DHCPv6 Relay Implementors regarding draft-ietf-dhc-dhcpv6-pd-relay-requirements
X-BeenThere: dhcwg@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <dhcwg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dhcwg/>
List-Post: <mailto:dhcwg@ietf.org>
List-Help: <mailto:dhcwg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 14 Oct 2020 22:27:43 -0000

I note that the lack of “challenge” does not mean anyone agrees.   Agreement needs to be affirmative.

Bob


> On Oct 14, 2020, at 3:24 PM, Templin (US), Fred L <Fred.L.Templin@boeing.com> wrote:
> 
> Bob, several messages back it was established that the issue at the heart of this
> discussion is not specific to DHCPv6 nor DHCPv6-PD. Instead, it is an issue that is
> common to any situation where there are multiple "stub" IPv6 routers on a
> downstream link from a "default" IPv6 router, no matter how the routing
> information is established or maintained. So far, no one has challenged my
> assertion that this is a generic (and not a DHCPv6-PD-specific) IPv6 issue and
> I have been waiting to see if anyone wants to challenge that.
> 
> Fred
> 
>> -----Original Message-----
>> From: Bob Hinden [mailto:bob.hinden@gmail.com]
>> Sent: Wednesday, October 14, 2020 2:47 PM
>> To: Templin (US), Fred L <Fred.L.Templin@boeing.com>
>> Cc: Bob Hinden <bob.hinden@gmail.com>om>; Michael Richardson <mcr+ietf@sandelman.ca>ca>; dhcwg <dhcwg@ietf.org>rg>; IPv6 List
>> <ipv6@ietf.org>rg>; v6ops list <v6ops@ietf.org>
>> Subject: Re: [EXTERNAL] [dhcwg] [v6ops] Re: Question to DHCPv6 Relay Implementors regarding draft-ietf-dhc-dhcpv6-pd-relay-
>> requirements
>> 
>> With my chair hat on, is there a reason why this discussion is being copied to the 6MAN w.g.?   6MAN doesn’t maintain DHCP related
>> items.
>> 
>> Please remove ipv6@ietf.org from this thread.
>> 
>> Bob
>> 
>> 
>>> On Oct 14, 2020, at 12:19 PM, Templin (US), Fred L <Fred.L.Templin@boeing.com> wrote:
>>> 
>>> Hi Michael,
>>> 
>>>> -----Original Message-----
>>>> From: Michael Richardson [mailto:mcr+ietf@sandelman.ca]
>>>> Sent: Wednesday, October 14, 2020 11:58 AM
>>>> To: Templin (US), Fred L <Fred.L.Templin@boeing.com>
>>>> Cc: ianfarrer@gmx.com; Jen Linkova <furry13@gmail.com>om>; dhcwg <dhcwg@ietf.org>rg>; v6ops list <v6ops@ietf.org>rg>; 6man
>>>> <ipv6@ietf.org>
>>>> Subject: Re: [EXTERNAL] Re: [dhcwg] [v6ops] Re: Question to DHCPv6 Relay Implementors regarding draft-ietf-dhc-dhcpv6-pd-
>> relay-
>>>> requirements
>>>> 
>>>> 
>>>> Templin (US), Fred L <Fred.L.Templin@boeing.com> wrote:
>>>>> Michael, what I was referring to below as "failure" is the proxy case when
>>>>> there is an L2 proxy P between the client and relay (e.g.,
>>>>> RFC489). There
>>>> 
>>>> RFC4389 describes an ND Proxy.
>>>> Is that really an L2 proxy?
>>> 
>>> Yes, I believe it is an L2 proxy.
>>> 
>>>> It seems like it also must be contain either an L2-bridge, or must have the
>>>> L3-routing table entries if it would really be capable of passing DHCPv6-PD
>>>> prefixes through it.
>>> 
>>> The only thing it has that includes L3 information is neighbor cache entries that
>>> keep track of the client's actual L2 address on the downstream link segment,
>>> but rewrites the client's L2 address to its own L2 address when forwarding
>>> onto an upstream link segment. (In the reverse direction, it receives packets
>>> destined to its own L2 address but the client's L3 address on the upstream
>>> link segment, then rewrites the L2 address to the client's L2 address when
>>> forwarding onto the downstream link segment.)
>>> 
>>>> Can you explain how such a device would normally work for a client device
>>>> A,B,C,D doing DHCPv6-PD through it?
>>> 
>>> Sure. A sends a DHCPv6 Solicit using its IPv6 link-local address as the source,
>>> and its L2 address as the link-layer source. The proxy converts the link-layer
>>> source to its own L2 address when forwarding the DHCPv6 solicit onto the
>>> upstream link. When the DHCPv6 Reply comes back, the IPv6 destination is
>>> that of client A, but the link-layer destination is the L2 address of the proxy.
>>> The proxy then converts the L2 destination to the address of client A and
>>> forwards it on to the client.
>>> 
>>>> And is the failure one where the router "R" fails to drop traffic it should,
>>>> one where the router "R" drops traffic that it shouldn't?
>>> 
>>> I was thinking more along the lines of the latter; if the only way that A has
>>> for talking to B, C, D, etc. is by going through R, it wouldn't work if R was
>>> unconditionally dropping everything.
>>> 
>>> Thanks - Fred
>>> 
>>>> --
>>>> Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
>>>>          Sandelman Software Works Inc, Ottawa and Worldwide
>>>> 
>>>> 
>>>> 
>>> 
>>> --------------------------------------------------------------------
>>> IETF IPv6 working group mailing list
>>> ipv6@ietf.org
>>> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
>>> --------------------------------------------------------------------
>