IPv6 Wow

Mohacsi Janos mohacsi at niif.hu
Mon Oct 13 11:24:41 UTC 2008

On Sun, 12 Oct 2008, Stephen Sprunk wrote:

> Mikael Abrahamsson wrote:
>> This brings up an interesting question, should we stop announcing our 6to4 
>> relays outside of Europe? Is there consensus in the business how this 
>> should be done? I have heard opinions both ways.
> I can understand why some folks would say stop, but unfortunately Europe has 
> the closest public 6to4 relays to the US, and our own providers don't seem to 
> want to put any up.  That means 6to4 will break for a great many folks who 
> _are_ trying to use IPv6 (like developers trying to get ahead of the curve 
> and make sure their apps don't break when the transition finally happens) but 
> whose providers haven't clued in yet.
> (My traceroutes to have a next-to-last hop in Amsterdam, and I'm 
> on one of the largest ISPs in the US, which apparently hasn't figured out 
> 6to4, much less native IPv6.)

The problem is that every tunneling mechanisms is selecting detination 
without the real knowldege about the underlying technology/distance etc. 
It was horrible during the 6bone - documented by Pekka Savola. We are not 
learning, from the past... 6to4 can generate same amount of problem....

Basically if they would obey the default address selection rules they 
would use 6to4 addresses only if there would be no global addressess and a 
resource would be acessible only from IPv6.

This is the intended and recommended behaviour which is implemented by 
Windows (XP, Vista), *BSD systems and recent Linux systems.

Unfortunately there is a broken idea of Apple to not implment RFC 3484 
style Default Address Selection into the protocol stack, however it is 
implemented in its ancestors (*BSD + KAME) for more than 4 years now.

Best Regards,

Janos Mohacsi
Network Engineer, Research Associate, Head of Network Planning and Projects
Key 70EF9882: DEC2 C685 1ED4 C95A 145F  4300 6F64 7B00 70EF 9882

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