Members of the Internet engineering community have raised several new security concerns about Teredo, a mechanism for sending IPv6 traffic over IPv4 networks that comes turned on by default in Microsoft’s Vista software.
Symantec and Ericsson security experts who called attention to the issue say they are concerned that Teredo bypasses network security through such devices as firewalls. Microsoft officials could not be reached for comment.
IPv6 is a long-anticipated upgrade to IPv4, the Internet’s primary communications protocol.
IPv6 fixes the lack of IP addresses found in IPv4. IPv6 has a virtually unlimited number of IP addresses, while IPv4 has 4.3 billion IP addresses, the majority of which have been handed out.
Teredo is a tunneling technique used to send IPv6 traffic through IPv4 network address translators (NAT). Because of the lack of IPv4 addresses, NATs are commonly used in enterprise networks to mask many private IPv4 addresses behind a single public IPv4 address.