On 13.07.2008, at 15:04, Manuel Kasper wrote:

> I've noticed the same - looks like the 6to4 gateway at SWITCH is  
> doing some strange kind of filtering: when I ping ipv6.sixy.ch from  
> a 6to4 address, I see the v6 echo requests coming in on the box that  
> hosts sixy.ch, and the replies going out. However,  
> 2001:620:0:c006::1 (swiCE2-10GE-1-3.switch.ch) sends back an ICMPv6  
> destination unreachable/prohibited...

For the record - SWITCH has identified and fixed the problem with  
their 6to4 gateway, so users within reach of their anycast  
announcement (.ch and who knows where else) should no longer  
experience problems reaching some IPv6 sites via 6to4.

- Manuel