Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com) [LWN.net]

Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com)

Posted Oct 22, 2010 21:00 UTC (Fri) by dlang (guest, #313)
In reply to: Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com) by lutchann
Parent article: Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com)

is there something similar to NAT64 that could be run on the home routers that would let people run IPv4 internally, NAT to IPv6 on the router, and then NAT64 back to IPv4 later?

I cringe at even typing this, but it may be better than having to tunnel everything to specific endpoints. If enough ISPs were to go this route, they could start peering to each other with IPv6 and the traffic would just get converted to IPv4 as it goes to the servers.

I don't think that the DS-Lite approach will have the results you are expecting, because customers will still be running NAT on their devices.

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Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com)

Posted Oct 23, 2010 14:51 UTC (Sat) by lutchann (subscriber, #8872) [Link]

> is there something similar to NAT64 that could be run on the home routers that would let people run IPv4 internally, NAT to IPv6 on the router, and then NAT64 back to IPv4 later?

That's called NAT464 and it's been discussed off and on as a possible transition tool, but I haven't seen a lot of support for it as DS-Lite is generally agreed to be the most robust approach. You'll probably see NAT464 in mobile phone networks to avoid the tunnelling overhead of DS-Lite.

> I cringe at even typing this, but it may be better than having to tunnel everything to specific endpoints. If enough ISPs were to go this route, they could start peering to each other with IPv6 and the traffic would just get converted to IPv4 as it goes to the servers.

Not sure I follow...if an IPv6-enabled host on one network wants to communicate with an IPv6-enabled host on another network, there will be no translators in the path. It will all be native IPv6. DS-Lite only tunnels and translates traffic headed for an IPv4-only destination.

> I don't think that the DS-Lite approach will have the results you are expecting, because customers will still be running NAT on their devices.

Regardless of the transition mechanism used, we have to expect that some people will just connect their old IPv4 NAT box to their shiny new v4/v6 box running DS-Lite or NAT464 or whatever. With DS-Lite, you'd then have double-NAT, and with NAT464, you'd then have triple NAT. It should generally work, it's just silly and adds one more point of failure.