Re: IPv6 only host NAT64 requirements?

Ole Troan <> Sun, 19 November 2017 01:03 UTC

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Subject: Re: IPv6 only host NAT64 requirements?
Date: Sun, 19 Nov 2017 02:03:23 +0100
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Cc: Jen Linkova <>, 6man WG <>, Mark Andrews <>
To: Brian E Carpenter <>
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> To be clear: I used ietf-nat64 all week, and all the things that didn't work
> are not an issue on a dual-stack network. From the host's point of view,
> dual-stack is definitively superior, IMNSHO, and nothing is going to
> change that. NAT64 is second-best. It may appear to be cheaper for some
> operators in some scenarios, that's all.

From that perspective, "IPv4 only" is still best. But that's not where we want to be, is it?

The original transition plan was for all networks, hosts and application to be dual-stacked, then when that point was reached, there would be no more traffic on the "IPv4 Internet" and it could be turned off. We now know that this point is not within sight.

Dual-stack as a transition is a failure. Dual-stack is a deployment model where we bear the cost caused by the IPv4 laggards.

IPv6 only + NAT64 is progress. It relegates IPv4 to the edges.
We want a situation where IPv4 only services are fronted by IPv6, and the cost born by those operating those services.

The challenge we have in front of us is to make IPv6 only work.