For some reason, Microsoft decided that Windows 7 would autoconfigure IPv6 using a random identifier (not the MAC address / EUI-64) – they went on to decide that it would randomly assign temporary addresses which change constantly. This is an admin nightmare, not to mention *awful* when it comes to assigning DNS.
So, here’s how to make Windows 7 behave as per every other OS…
1. Open up a Command Prompt in Administrator mode (right-click, run as administrator)
2. Run the following commands. Each one should respond “Ok”. If you didn’t do step 1 correctly, it will say the command required elevation.
netsh interface ipv6 set privacy state=disabled store=active
netsh interface ipv6 set privacy state=disabled store=persistent
netsh interface ipv6 set global randomizeidentifiers=disabled store=active
netsh interface ipv6 set global randomizeidentifiers=disabled store=persistent
3. Exit the command prompt, and reboot.
When your computer has rebooted, it should auto-configure itself using EUI-64 (based on the MAC address of the interface) within the subnet given in the router advertisement.