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I have a network mapped like this :

enter image description here

To experiment with IPv6 connectivity, I want to configure my LAN network using IPv6.

Can someone explain how to convert the connection between the Desktop and the Laptop to IPv6 without losing the Internet connection?

I don't want to access IPv6 Internet, I need to keep v4. The end result should be something like a full-IPv6 Laptop accesing IPv4 Internet over a somehow-configured Desktop acting as a NAT.

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+1 for explaining the question well – rzlines Oct 24 '09 at 20:37

If I understand your diagram correctly, the Laptop does not have direct access to the Router, it accesses the Internet through the Desktop behind a two-level NAT (Router, then Desktop). This setup is quite strange, there is no need for an additional address translation, you can just put the Laptop in the same subnet ( as the Router and the Desktop, and let it communicate directly with the Router, or use the Desktop as a simple router (without address translation) if the Router doesn't have wireless interface.

You will not "convert" the Laptop to IPv6, since that would hinder your ability to browse the Internet (since your router and most of the Internet still doesn't support IPv6). What you want is to install the IPv6 stack in parallel to the current IPv4 stack in both Desktop and Laptop. You run both protocol stacks side-by-side, at the same time. The IPv4 will continue to be used to access everything that is still IPv4, and the IPv6 will be used to access IPv6-enabled sites. Enabling the IPv6 stack in both your hosts will allow them to talk to each other using the IPv6 stack (as well as IPv4).

To start using IPv6 between your hosts, just go to network connections in control panel, open the properties box of your network adapter and install the TCP/IP version 6 protocol in both machines. You don't need to configure any address, they will assign IPv6 addresses themselves automatically in the fe80::/10 prefix (if there was an IPv6 router present on your network, other (routeable) addresses would also be configured automatically).

To access the IPv6 Internet is a little more complicated, since your router doesn't have IPv6 support, and I bet your ISP also still doesn't provide you direct IPv6 access. You need to transport IPv6 over your current IPv4 Internet. The easiest way to do that is to use Teredo tunneling. You will find information on how to configure that on the Microsoft website. Usually, this command is enough:

netsh interface ipv6 set teredo client

To check your IPv6 addresses:


There are other options, like using a Tunnel broker, but these are usually a little more complicated to setup.

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thanks Juliano, but the Wifi-A is a shared connection, so, the Wifi-B need to be, right ? (Ive edited the diagram to make it more clear), right now I don't want to access IPv6 internet, just make the Wifi-C & Wifi-B IPv6-based and a 6to4-tunnel between Wifi-A & Wifi-B (it seems I will need a DNS translation from 6 to 4) Im really confused, is this the best approach ? – user8228 Oct 25 '09 at 16:46
@Revolter: You are welcome. In theory, you shouldn't need to make Wifi-A a shared connection and you also don't need the Wifi-B at all. Is there any restriction for you not to connect the Laptop Wifi-C directly to the cell that contains the Router and the Desktop's Wifi-A? – Juliano Oct 25 '09 at 17:27
Im using the Desktop like a repeater, the Laptop can't reach the router wifi range – user8228 Oct 25 '09 at 17:30
Ok... Then your case is peculiar. It is strange to put the laptop behind two NATs (what Windows call "Shared connection" is what everyone understands as NAT), but is should be ok. To enable IPv6 over Wifi-B and Wifi-C just follow the instructions above. A 6to4 tunnel between Wifi-A and Wifi-B doesn't make sense, since they are in the same machine. It may be easier if you explain the end result you expect, perhaps you have a wrong understanding about what you can get with IPv6. – Juliano Oct 25 '09 at 17:50

YOu would need a DHCP server running on the desktop to automatically give out an IP address to the Laptop with IPv6, or you can manually edit these options from Control Panel\Network and Internet\Network Connections on the windows 7 laptop with the default gateway based on the B adapter, assuming thats the port used by the desktop running the IPv6 DHCP server.

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There is no need for any DHCP server. DHCP is used for IPv4, not IPv6. There is the IPv6 equivalent, but it is called DHCPv6, and it has a somewhat different purpose. DHCP was used for IPv4 mostly for address autoconfiguration, which is now part of IPv6 stateless address autoconf and NDP, no sort of DHCP is necessary. – Juliano Oct 25 '09 at 15:33

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