Best practices for routing 6to4 addresses

Rémi Denis-Courmont rdenis at
Tue Oct 17 20:05:45 CEST 2006


Le mardi 17 octobre 2006 18:00, Daniel G. Kluge a écrit :
> I was wondering if there is some consensus on how to deal with 6to4
> (2002::/16) addresses (and of course this applies to a certain extent
> to Teredo).
> There are three ways how to configure this in an IPv6 network, and I
> think I've seen all three:
> 1. Configure a 6to4 relay on each router (which has to be dual-
> stacked) and use the local interface as a static route.

I'm no operator, but I don't think anybody operating more than a single 
home router would try that.

Also, one must make sure the IGP is not multi-path-routing 6to4, and IN 
ANY CASE NOT Teredo from anywhere. The latter protocol would completely 

> 2. Have only one central 6to4 relay which is advertised internally
> (and maybe further).
> 3. Pray that you learn 2002::/16 over one of your peers or transit
> providers (and fail - hello AS16215)

> What's the way to go?

I would say (2) if you can give the minimalistic but non-null care such 
a setup needs, (3) otherwise. I guess, one might want to have multiple 
relays, à la (1), if one operates IPv4-enabled sites across multiple 
continents, though.

> (Apart from not using 6to4 or any other 
> automated transition mechanism)

...which does not solve much of the problem since it is not you who 
decides whether IPv6-enable nodes who wants to talk to your nodes use 
6to4, Teredo or what not :(

Rémi Denis-Courmont

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