Maybe I missed it, but was there some concerted effort to remove or block access to the 2002::/16 route on the v6 backbone in North America recently? Connectivity to/from 6to4-only hosts seems sketchy at best. Of the US hosts I've tried, only ISC has responded at all to a 6to4 packet -- and they're routing 2002::/16 through WIDE in Japan from what I can tell.
From about half the US IPv6 looking glasses I've tried, the route is missing entirely. By contrast, I can see it everywhere, typically from multiple upstreams, in JP (no surprise there), CH, DE, and FR that I've tried so far.
I haven't been using 6to4 for almost 6 months now, but this seems like a really alarming step backwards as far as v6 adoptability goes in dynamic v4-pool environments. Yes, I'm aware of the security implications of 6to4 -- but if the RFC-suggested header address checks are properly performed at the ingress 6to4 gateway, the burden of security falls on the 6to4 user alone, which is (IMHO) an acceptable situation. -- -- Todd Vierling <tv@duh.org> <tv@pobox.com> <todd@vierling.name>