Re: [shim6] Exit selection [New Version Notification - draft-mrw-nat66-08.txt]

Brian E Carpenter <> Sun, 13 March 2011 23:15 UTC

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Date: Mon, 14 Mar 2011 12:16:39 +1300
From: Brian E Carpenter <>
Organization: University of Auckland
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To: Geoff Huston <>
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Subject: Re: [shim6] Exit selection [New Version Notification - draft-mrw-nat66-08.txt]
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On 2011-03-14 11:58, Geoff Huston wrote:
> On 14/03/2011, at 8:23 AM, Sander Steffann wrote:
>> Hi Geoff,
>>> From my memory I believe it was because some folk  thought that a) unicast reverse route filtering would be prevalent in IPv6 and that b) clients could not negotiate filters with their provider.  But is a) true? and is b) really true? Frankly I'm pretty sceptical that this is the case and it concerns me that this is a case of over solving.
>> From my personal experience here in The Netherlands: a) yes, b) yes. At least for home users and small/medium sized businesses. A lot of them use cheap DSL based internet access, and they do uRPF for IPv4 and refuse to deploy an IPv6 service that can not do uRPF. And because the service is cheap, the ISP has no budget for b)...
> wg co-chair hat still off
> It may be (is?) heretical in the context of this wg, but at the low end of the market that is highly cost and process constrained, as the subject line refers, NAT66 is an obvious approach that does not try and jump through the trapeze hoops of trying to do hop-by-hop forwarding based on source address in a general manner..

If you mean NPTv6, yes, it's heresy but it will no doubt get its
share of the market. I see shim6 and multihoming-without-nat as
part of the longer term future for medium scale enterprise sites.