IPv6 Wow

Joe Abley jabley at hopcount.ca
Fri Oct 24 03:08:18 UTC 2008

On 23 Oct 2008, at 18:46, Alain Durand wrote:

> On 10/23/08 6:39 PM, "Tony Hain" <alh-ietf at tndh.net> wrote:
>> A properly
>> implemented client will do the longest prefix match against that  
>> set, so a
>> 6to4 client will go directly to the content provider's 6to4 router,  
>> while a
>> native client will take the direct path.
> Not quite.
> Say the server has native IPv6 address 2001::1 and 6to4 IPv6 2002::X.
> Say the client has native IPv6 address 2003::1 and 6to4 IPv6 2002::Y.
> Longest prefix match will choose 6to4 over native IPv6. Not good.

Surely the longest prefix only wins over prefixes that cover the long  

What you seem to be suggesting is that a client will somehow be able  
to deduce the prefix length for two bare v6 addresses received from  
the DNS, and will choose the one with the longest prefix first. That  
seems unlikely to be the case in general.


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