Re: [dhcwg] [Last-Call] Iotdir last call review of draft-ietf-dhc-v6only-03

Ted Lemon <> Tue, 23 June 2020 17:29 UTC

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From: Ted Lemon <>
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Date: Tue, 23 Jun 2020 13:28:56 -0400
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Cc: "Pascal Thubert (pthubert)" <>, "" <>, "" <>, "" <>, "" <>
To: Philip Homburg <>
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Subject: Re: [dhcwg] [Last-Call] Iotdir last call review of draft-ietf-dhc-v6only-03
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On Jun 23, 2020, at 1:07 PM, Philip Homburg <> wrote:
> I consider NAT64-to-hosts a really bad idea. Implementing 464xlat in a CPE
> or other router is not that bad, but making sure that every host in your
> network can properly support NAT64 or 464xlat is not something you should
> want.

On the other hand, if you use 464xlat, it means that every endpoint needs to speak IPv4. This is a significant added cost for constrained devices. So requiring IPv4 and 464xlat on these devices seems like a much higher cost than using NAT64 for the cases where some non-constrained endpoint can’t speak IPv6 for some reason, or isn’t reachable over IPv6. The set of cases where this is necessarily true may not be that large. E.g., the most sensible case would be connecting to the cloud; in this case, NAT64 works fine.