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Assume the following scenario regarding the current IPv4/OpenVPN setup:

        Central Site with a /64 IPv6 (
        |                         |
OpenVPN Server A          OpenVPN Server B
 (             (
        | |                       |
        | |                     [n-m]
        | |                     / | \
        | \            Multiple Remote Clients (10.10.0.x)
        |  \
        |   \_____________________
        |                         |
 Local Site A              Local Site B
 (             (

Additional background information: Each local site has a Netgear WNR3500L/U/v2 running Tomato Firmware v1.28.9054 MIPSR2-beta K26 USB vpn3.6 which was built on Tue, 30 Nov 2010 14:49:14 -0500. The central site runs a bind instance to handle DNS requests from the local sites and forwards requests down to the corresponding local site with regards to the sites specific subdomain. The other way around the local sites forward non-local lookups to the central site using dnsmasq.

The whole network is created using tun devices and therefore there is no bridging in place. Since routing and forwarding is required the central site uses OpenVPN's push to setup the required routes on the local site gateways.

Now I would like to make use of the /64 network I was given and distribute it among the local computers behind the gateways on each local site. A bonus would be to also have the other remote clients (10.0.0.x) pickup an IPv6 address.

The goal would be to use the local IPv4 address to create a new IPv6 address with 2a00:xxxx:xxxx:xxxx:central-prefix:local-prefix::10.x.x.x

Another goal would be to have the OpenVPN server and/or TomatoUSB based gateway do the heavy lifting of this. The reason is that the clients behind those gateways are mixed operating systems and devices.

Any suggestions and/or solutions are highly appreciated. Thanks in advance!

share|improve this question
"Since routing and forwarding is required" you really should have more than a single /64. Your ISP should have given you a /56 or even a /48. – Michael Hampton Jan 5 '13 at 16:09

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