Teredo is a technology use to encapsulate IPv6 packets in IPv4 packets when the network devices do not support IPv6 standard. This allows the transmission of packets via devices using address translation or on the Internet using IPv4.
IPv6 and Teredo installed by default on Windows Vista, Windows 7 and Windows 8. *These drivers can't be uninstalled! However, if IPv6 support is not enabled on your OS, the Teredo client is activated (but remains idle).
It is automatically activated when an application need to use IPv6. Once enabled it will need to find the IPv4 address corresponding to each IPv6 address.
This is achieved by performing a DNS query to teredo.ipv6.microsoft.com. If you use a firewall (like ZoneAlarm), it will block the connection and prevent the client from running. This usually results in a yellow exclamation mark in the device manager.
Enable IPv6 on your Firewall
In the settings of your firewall, click Advanced Options and make sure the "Enable IPv6" checkbox is check.
Reboot if necessary.
If you do not want the client initiate the connection or you do not want to use Teredo (most software work without it), you can disable the Teredo client:
Via the Device Manager:
Open the Device Manager
Open the "Network Adapters"
Click on the View menu > Show hidden devices.
Right click on the device and select "Disable" button.
Using the command prompt:
Click Start > All Programs > Accessories .
Right click on "Command Prompt" and select "Run as administrator".