I have two Windows XP machines running Teredo. They are connected to the same switch, however, I cannot ping from one to the other using the Teredo IP addresses. I am able to ping a host outside of the network (global IPv6 address). Is this a configuration issue on my part or is there a known issue here?Thanks,Jason.

Are you using winxp sp3? I too face the same problem but it works fine between two xp sp2. In xp sp3, teredo should send a multicast bubble packet from local ipv4 adddress when both clients are behind same NAT, that's seems to be missing in xp3.