Re: [dhcwg] DHCP Relay and Prefix Delegation

Ian Farrer <> Mon, 25 July 2016 15:08 UTC

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From: Ian Farrer <>
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Date: Mon, 25 Jul 2016 17:08:15 +0200
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To: Alexandre Petrescu <>,
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Subject: Re: [dhcwg] DHCP Relay and Prefix Delegation
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Hi Alexandru,

Thanks for the pointer to the document. I’ve had a look through it and whilst it’s certainly related, the specific problem that I’m seeing in vendor’s implementations is only really touched upon in Section 5.1. Yes, snooping is implemented, but the way that this is implemented, the messages that do/don’t get forwarded and the errors that get generated when things are not working are pretty much variable from vendor to vendor (and in one case, there are two different implementations in the same platform with differing behaviours).

I would like to see an effort to define this behaviour better and volunteer to work on it. I’m not sure whether this draft is necessarily the right starting point as it’s more concerned with the route advertisement part of the problem and enumerating ways that this could be performed, but it really depends on how this problem is scoped.

I’m also aware that RFC7513 section 6 has quite some detail of how DHCPv6 snooping works in SAVI for DHCP. I haven’t been through this in detail yet, but it’s probably got useful stuff in there.


> On 20 Jul 2016, at 17:00, Alexandre Petrescu <> wrote:
> Hello,
> There was a discussion today in the DHC WG meeting about the DHCPv6bis XML.  One issue raised was that maybe a clarification was needed about the problem of a Relay in a DHCPv6 Prefix Delegation setting.
> We wrote a draft earlier on a problem in this setting:
> draft-petrescu-relay-route-pd-problem-00
> Alex
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