[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: draft-huitema-v6ops-teredo-03.txt


Hi Eric,

I am not quite sure how to respond to your post, because I am not sure that parts of it are applicable to Teredo at all...

At 6:11 PM +0200 12/5/04, EricLKlein wrote: 
I am still a little uncomfortable about the fact that there is no explicit
statement that "teredo is needed because NAT was deprecated in IPv6 so
teredo is needed to allow IPv6 nodes to communicate with IPv4 nodes in a
domain that utilizes NAT."

While we can certainly hope that IPv6<=>IPv6 NAT is never necessary, it is not possible for the IETF to "deprecate NAT in IPv6". If administrators ever have a reason to use NAT in IPv6, there is nothing we can do to stop them.

Or are you talking about NAT-PT (Network Address Translation with Protocol Translation) that translates between IPv4 and IPv6?

If you are talking about NAT-PT, then I still don't understand your point. Teredo allows access to the IPv6 Internet for IPv6-capable nodes that are located behind an IPv4 NAT on networks where their ISP does not provide native IPv6 service. Those nodes cannot tunnel to the IPv6 Internet using other defined methods (i.e. 6to4) because those methods don't work through an IPv4 NAT. Teredo is merely a mechanism to set-up the tunnel through an IPv4 NAT, so that IPv6 connectivity can be obtained.

Teredo really doesn't have anything to do with IPv6<=>IPv6 NAT or NAT-PT.

This is still true in section 3.2.4 Automatic sunset.
Some how this whole section scares me as it seems to imply that there is a
way to turn an IPv4 NAT into an IPv6 Router while maintaining the NAT like
functionality. As stated above, NAT is not part of IPv6 (NAP is but is still
not mentioned in this document).

In time, I actually expect that there will be home gateways that provide IPv4 NAT and IPv6 routing with a stateful firewall for protection. At least, I hope so. If I have a router like that _AND_ my ISP offers native IPv6 connectivity, then I won't need Teredo. That's what the sunset clause is all about... Why is that scary?

Margaret