Teredo is a transition technology that allows a computer or node located behind a IPv6-unaware network address translation (NAT) device to use IPv6 connectivity to communicate with other computers that use IPv6. Teredo tunneling technology defines a way of encapsulating IPv6 packets within IPv4 UDP datagrams that can be routed through NAT devices and on the IPv4 internet. IPv6 and Teredo is installed and enabled by default in Windows Vista, and users cannot uninstall them.
Users can turn off IPv6 support in Vista. Teredo client in Windows Vista is enabled but inactive by default, but it will activate automatically when required or firewall settings allow an application to use Toredo. When activated, the Teredo client must initially obtain information such as the type of NAT that the client is behind by connecting to one or more Teredo servers. To determine the IPv4 addresses of Teredo servers, the client may send a DNS query to resolve the name teredo.ipv6.microsoft.com. To prevent Teredo related DNS query, or for those who doesn’t use Teredo or IPv6, users can disable or control Teredo in Windows Vista by using the following methods. Microsoft confirms that it is usually workable to disable Teredo, because other technologies can be used instead, for example, Intra-Site Automatic Tunnel Addressing Protocol (ISATAP).
Turn Off Teredo by Using the Netsh Command
- Open elevated command prompt by clicking on Start, click All Programs, click Accessories, right-click Command Prompt, and click Run as Administrator.
If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
- At the command prompt, type the following lines (press ENTER after each line):
- At the netsh interface teredo command prompt, type:
set state disabled