By default, when configuring an IPv6 address, Windows 8 generates a random number to fill out the bits needed for the NIC portion of the IPv6 address. This security measure helps conceal your devices MAC address, and further protects your privacy by generating a new number every so often. There may be times, however, when you need your system to maintain a static IPv6 address. To do this, you can disable the temporary IPv6 address feature using the Netsh utility in an elevated command prompt window. Do the following:

1. Open an elevated command prompt window.

2. Find your computers current IPv6 address and MAC address. Carefully compare the two addresses. Are they in any way numerically related?

3. To disable the random IP address generation feature, enter the command:

netsh interface ipv6 set global randomizeidentifiers=disabled

4. To instruct Windows to use the EUI-64 standard instead of the default settings, use this command:

netsh interface ipv6 set privacy state=disabled

5. What is your computers new IPv6 address? Notice that the fixed value FF FE has been inserted halfway through the MAC address values in the second half of the IPv6 address. Note that the host portion of the IPv6 address may look slightly different because of the way the values are converted for use by IPv6. Recall that the seventh bit of the MAC address is inverted, resulting in a slightly different value.

6. Reenable random IPv6 address generation with these commands:

netsh interface ipv6 set global randomizeidentifiers=enabled

netsh interface ipv6 set privacy state=enabled