6to4 strangeness

[Iljitsch van Beijnum]

Hi ipv6-ops,

I'm seeing a 6to4 problem that I haven't seen before... Maybe one of  
you can explain this. Today, http://www.osx86project.org/ announced  
that they are IPv6-capable. But it didn't work for me: with a source  
address in 2001:1af8::/32 with UUNET NL as a main transit network I  
was unable to reach the site. Turns out they use a 6to4 address  
(based on the IPv4 address 66.235.180.107): 2002:42EB:B46B::2.

When I added a 6to4 interface to my router, everything worked with a  
6to4 source address:

#trace
Protocol [ip]: ipv6
Target IPv6 address: www.osx86project.org
Source address: 2002:52C0:5A19::1

   1 www.osx86project.org (2002:42EB:B46B::2) 96 msec *  100 msec

But not with a regular production address:

#trace
Protocol [ip]: ipv6
Target IPv6 address: www.osx86project.org
Source address: 2001:1AF8:6:0:204:27FF:FEFE:249F

   1  *  *  *
   2  *  *

So apparently the route from them back to me is broken. For reasons  
unknown, I also tried it with a 6bone address:

#trace
Protocol [ip]: ipv6
Target IPv6 address: www.osx86project.org
Source address: 3FFE:2500:310:3:204:27FF:FEFE:249F

   1 www.osx86project.org (2002:42EB:B46B::2) 396 msec 384 msec *

This means that for them, or rather, their 6to4 gateway, my  
2001:1af8::/32 address is unreachable, but 3ffe:2500::/32 works. WTF?

-- 
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