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On a WAN I have 5 different locations connected by point to point T1s via Cisco 2801s, with one central location routing each location to all the others, sort of a star configuration.

The routers' iOS is too old and doesn't support IPv6, so in order to get some testing done using ULAs, I wanted to essentially tunnel over them and at each location have a FreeBSD server serving as a sort of tunnel broker, or something, and a gateway for the IPv6 machines at said locations.

I'm new to IPv6, but I can't seem to find examples or proper terms for exactly what I'm interested in doing. I can find examples of FreeBSD gateways and external tunnel broker connections, but nothing for routing IPv6 across your own IPv4 WAN.

Any insights would be greatly appreciated.

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With such a network, you should use your ciscos and go native ipv6. If your IOS doesn't support ipv6 it's time to upgrade at least to correct bugs & security holes (security updates provided for free by cisco). – petrus Sep 30 '11 at 9:46
@petrus that'd be my ideal, but i already have spare machines and FreeBSD is, well, free. It costs a decent amount of money to update 6 routers. – The Real Roxette Oct 1 '11 at 2:17
up vote 1 down vote accepted

You can connect your sites to central point via gif(4) tunnels and use IPv6 inside these tunnels. This will correctly encapsulate/decapsulate IPv6 in IPv4, but this approach is useful only when you have static public IPv4 addresses. If you have dynamic IP it's better to use mpd to establish L2TP tunnels with IPv6 inside.

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Each location is a point-to-point T1, with static addresses like 10.x.0.1 so I think this will be equally beneficial as having a static IP across the Internet on both sides? – The Real Roxette Sep 30 '11 at 18:10
sure. And you can even run IPv6 without tunneling at all, since you already have point-to-point links between sites. – gelraen Oct 3 '11 at 6:34

You may want to use either 6to4 or 6in4 tunnels. Once you have the tunnels up you will need to add the appropriate routing entries to your FreeBSD tunnel brokers.

6to4 will give you networks based on the IPv4 address of your brokers. 6in4 will route IPv6 packets as data inside IPv4 packets. It is more flexible.

There is a lot of documentation on using these protocols to provide IPv6 Internet access to systems with only IPv4 Internet connectivity. This is how I provide IPv6 access to my systems. (Not that there is a lot of traffic yet.) I started with a 6to4 tunnel, and migrated to a 6in4 tunnel to Hurricane Electric.

Hurricane Electric provide a fair bit of documentation on their site. Even if you don't enable IPv6 Internet access, you can used the same principles.

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