The more out-of-the-box your setup is, the more likely it'll work (modulo a few broken OS/browser combos listed in the ARIN wiki).
You might experience problems in environments where someone has been playing with IPv6 and left it half-broken (or, in my case, tried to be too smart and used DNS server on Cisco router ;)
You might experience problems in environments where someone has been playing with IPv6 and left it half-broken (or, in my case, tried to be too smart and used DNS server on Cisco router ;)