NAT444 or ?

Cameron Byrne cb.list6 at
Thu Sep 1 18:52:44 UTC 2011

On Thu, Sep 1, 2011 at 11:36 AM, Serge Vautour <sergevautour at> wrote:
> Hello,
> Things I understand: IPv6 is the long term solution to IPv4 exhaustion. For IPv6 to work correctly, most of the IPv4 content has to be on IPv6. That's not there yet. IPv6 deployment to end users is not trivial (end user support, CPE support, etc...). Translation techniques are generally evil. IPv6->IPv4 still requires 1 IPv4 IP per end user or else you're doing NAT. IPv4->IPv6 (1-1) doesn't solve our main problem of giving users access to the IPv4 Internet.

Correct, all content is not there yet... but World IPv6 Day showed
that Google, Facebook, Yahoo, Microsoft and 400+ others are just about
ready to go.

IPv6->IPv4 does not require 1 to 1, .... any protocol translation is a
form of NATish things, and stateful NAT64 has many desirable
properties IF you already do NAT44.  Specifically, it is nice that
IPv6 flows bypass the NAT .... and as more content becomes  IPv6, NAT
becomes less and less used.  In this way, unlike NAT44 or NAT444,
NAT64 has an exit strategy that ends with proper E2E networking with
IPv6... the technology and economic incentives push the right way
(more IPv6...)

Have a look at

There are multiple opensource and big vendor (C, J, B, LB guys...)
implementation of NAT64 / DNS64 ... I have trialed it and plan to
deploy it, YMMV... It works great for web and email, not so great for
gaming and Skype.

> I expect like most companies we're faced with having to extend the life of IPv4 since our users will continue to want access to the IPv4 content. Doing that by giving them an IPv6 address is not very feasible yet for many reasons. NAT444 seems like the only solution available while we slowly transition over to IPv6 over the next 20 years. Based on the this RFC, NAT444 breaks a lot of applications!

This is just putting IPv4 on life support without moving needle
towards a long term solution. NAT64 = good investment to get IPv6 off
the blocks.  NAT444 = life support / money pit with forklift exit

> Has anyone deployed NAT444? Can folks share their experiences? Does it really break this many apps? What other options do we have?

Yes, expect it to be deployed in places where the access gear can only
do IPv4 and there is no money or technology available to bring in


> Thanks,
> Serge

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