said by 56885201:
Interesting. I am on a Windows XP PC behind a WNR1000v2-VC NAT router that is using the Comcast 6t04 relay, and IPv6 seems to be working just fine for me (with the MS Teredo explicitly disabled):
I understand your router is doing 6to4 and announcing it (just like it would with ULA. or a unicast global).
My point was more to the fact that the poster had said Windows was using the built in 6to4 adapter. This is where Windows itself open a 6to4 tunnel. This is incorrect as it cannot be done behind NAT which should probably be pointed out so others browsing don't go enable 6to4 behind their router.