On 13.07.2008, at 11:45, Marcel Wiget wrote:

> Here a few more IPv6 test sites as I can't reach http://ipv6.sixy.ch
> nor ipv6.m0n0.ch (6to4 packets go out the WAN but no response comes
> back):

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...

When I shut down the IPv6 BGP peering sessions with SWITCH on the  
network that sixy.ch is on, it works fine (the replies then get routed  
through a 6to4 gateway in AS3344). Time to contact SWITCH I guess...

- Manuel