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Re: Creating demand for IPv6

  • From: William Herrin
  • Date: Wed Oct 03 19:45:08 2007
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On 10/3/07, [email protected] <[email protected]> wrote:
> > As mentioned, 6to4 doesn't do what you seem to think it does.
> > Its not a solution to the problem of IPv6 endpoints trying to
> > talk to IPv4 endpoints.
> I see that you did not change anything on that page. Specifically what
> is wrong with the wording below?


I could quibble about the description that it "requests dynamic
tunnels." Nothing is requested. Its comepletely stateless. There's no
setup or teardown. It just sends packets that get encapsulated and
decapsulated as they're received. But the description is not

Where in the description you posted did you read anything that
suggests it allows IPv6 endpoints to communicate with IPv4 endpoints?

> > Looks interesting. There's some version 0.4 user-space
> > software for Linux which claims to do
> You know, you could have added that to the page yourself. In any case, I
> added a pointer to a Cisco product brief that mentions they have
> upgraded NAT-PT to CEF in 12.4.

I generally wait until I've seen something actually work before
documenting how it works.

I haven't dug too deep into NAT-PT, but an obvious question comes to
mind: Why would an ISP deliver an IPv6-only connection plus NAT-PT
(and all the likely problems) with a surcharge for IPv4 instead of
delivering RFC1918 IPv4 + NAT with a surcharge for routable IPv4?
Without looking decades ahead to the waning days of IPv4 when its
desirable to minimize the IPv4 footprint in your network, I haven't
been able to come up with an answer. When I do, I'll take another look
at NAT-PT.

Bill Herrin

William D. Herrin                  [email protected]  [email protected]
3005 Crane Dr.                        Web: <>
Falls Church, VA 22042-3004