Let me explain how and why use it.
The actual purpose of using 6to4,Teredo is the temporary tunneling services
on testing line.
It supports automatic tunneling with outisde of IPv6 network as being
address a single IPv6 prefix which has the form of 2002:IPv4 address::/48
to IPv6 only websites that has more than 1 IPv4 address.
It means it’s not the pure IPv6 system.
As a result of that addressing, those IPv6 adresses are isolated,
they can’t connect the other sites and hosts.
So, ‘6to4’ makes the isolated IPv6 sites and hosts can communicate
to the other IPv6 domains and hosts with automatic tunneling system.
IPv4 to IPv6 tech had been developed, sevral years ago, but there was
no other way to use it in the private network of the inside NAT.
But oneday, Microsoft had suggested ‘Teredo’ which
was brand new IPv4 to IPv6 tunneling(exchange) system under Windows XP SP1,SP2+
‘Advanced Networking Pack’ environment.
So, people who belong to the private network in the NAT can use IPv6.
Teredo is IPv4 to IPv6 tunneling tech which uses UDP tunneling tech.
So, people who are using routers in the home and small office can use
There are some problems with those virtual IPv6 systems.
Sometimes,when people can be connected with IPv4 even if there is IPv6 address.
Because in case of Teredo tunneling, Teredo tries to connect IPv4/IPv6 dual stack websites.
Also sometimes, Teredo address is disappeared because of the network impediment.
When it happens we need to recover it.
Both 6to4 and Teredo are not the Pure IPv6 system but the virtual IPv6 system.
In the real world?
Visit following websites instead of you linked please.
You will see what real world do,how and what other countires are preparing for Pure IPv6
,other countires are doing for Pure IPv6.
Real IPv6 world organization.
The world doesn’t want to play with toys Teredo, 6to4.
The world wants to play with Pure IPv6 with real IPv6 equipments.