Question about 6to4

Kevin Loch kloch at
Fri May 15 16:59:16 CEST 2009

Erik Kline wrote:

> 2009/5/14 Kevin Loch <kloch at <mailto:kloch at>>

>     I can't recommend the proliferation of public relays as they
>     cause more problems than they solve.  Private relays are another
>     story as they help mitigate the problems of the anycast relays.  If
>     every service provider ran private 6to4 relays for their customers
>     it would be a Good Thing.
>     - Kevin
> The problem is that only addresses half the flow.  You've succeeded in 
> helping your customers get their packets onto the IPv6 Internet 
> efficiently (yay!).  But to get them back 1 of 2 things needs to happen:
>     (1) Every content provider/destination needs to have good, and 
> preferably local, access to a 2002::/16 return device so it can re-encap 
> the packets and send them to their IPv4 origin.  Otherwise they go off 
> into wherever 2002:/16 happens to point at that time.
> Obviously, this doesn't scale so well.

Actually, that is exactly what I meant.  ISP's and hosting/content
providers should have local and 2002::/16 relays
whenever possible.  Every relay closer to the endpoints helps.

The more IPv6 is deployed and used the larger the
6to4 problems will become.  Eventually running local 6to4
relays will need to be as common as local DNS resolvers.

- Kevin

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