Re: IPv6 only host NAT64 requirements?

Brian E Carpenter <> Mon, 20 November 2017 23:44 UTC

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Subject: Re: IPv6 only host NAT64 requirements?
To: Jen Linkova <>, "Manfredi, Albert E" <>
Cc: 6man WG <>
References: <> <787AE7BB302AE849A7480A190F8B93300A07AD68@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <> <787AE7BB302AE849A7480A190F8B93300A07C625@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <> <787AE7BB302AE849A7480A190F8B93300A07D481@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <> <787AE7BB302AE849A7480A190F8B93300A07D534@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <> <787AE7BB302AE849A7480A190F8B93300A07D63D@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <> <> <> <>
From: Brian E Carpenter <>
Organization: University of Auckland
Message-ID: <>
Date: Tue, 21 Nov 2017 12:44:52 +1300
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On 21/11/2017 09:33, Jen Linkova wrote:
> On Tue, Nov 21, 2017 at 7:12 AM, Manfredi, Albert E
> <> wrote:
>> Very instructive thread for me, I must say. I'm getting this sense of urgency, to be rid of IPv4, but it comes from the IETF 6man wg and some ISPs.
>> Ultimately, it's not up to 6man to decide.
> I do not see this thread as 6man deciding that everyone is to get rid
> of Ipv4 right now. I see it as 'there are networks deploying IPv6-only
> hosts and 6man is discussing how to help hosts to operate in such
> environment'.

Fair enough. But now, and for many years, IPv6-only hosts** will
be unusual (except on some cellular networks); IPv4-only hosts are 
common, and dual stack hosts are common.

** In my book, a host that contains even one IPv4-only application
cannot be considered as an "IPv6-only" host.
>> It's up to device vendors,  and up to the deployed base of devices.
>> The IETF can only suggest, and ISP networks have to meet the real world needs.
> People from the real world is coming to IETF saying 'we are deploying
> Ipv6-only hosts' [1] [2]

Sure. And I think the tests last week showed two things:
1. NAT64/DNS64 is viable for IPv6-only hosts (setting aside DNSSEC).
2. IPv6-only hosts are far from universal, even among IETF

And BTW thanks for the effort behind ietf-nat64. I think it
was a very valuable effort.