RE: Cannot ping with IPv6

Firstly I ran (in PowerShell):
netsh interface ipv6 teredo show state

This gave me information on the state of Teredo (which was inactive because
of an error). I re-enabled Teredo using the disable/set commands with the
entrepriseclient option, followed by:
netsh interface ipv6 reset

After a restart (not sure this was necessary) everything seemed to work
fairly well. I could ping IPv6 servers and view IPv6 websites (only some
however, but I believe this limitation is due to the MS Teredo server).

I later found out that it is impossible to get it working on XP with my
network configuration, since my router has a symmetric NAT and the version of
Teredo for XP does not support symmetric NATs (Vista has partial support for
symmetric NATs).

Not sure how common this problem is, but I only found it documented
(inconclusively) on one web page after much searching. Hopefully this
solution will help some of you trying to get IPv6 working on Vista...