Security company Symantec says new research supports fears that Windows Vista's use of the IP tunneling protocol Teredo is potentially insecure. Microsoft is using Teredo to enable a transition from IPv4, which is the traditional version of the network layer protocol for packet-switched networks now used as the Internet's background, to IPv6, an updated protocol whose biggest benefit is the exponential increase it will bring in the number of IP addresses available for networked devices. ExtremeTech has more.