I came across this post somewhere on the web – still trying to get back to it so I can link back here.
The interface identifier is not created according to RFC 4941, meaning there are potential issues lurking in an IPv6 deployment with Win7 machines and network hardware. Run the following command to fix:
netsh interface ipv6 set global randomizeidentifiers=disabled
Found the web site where I got the above information: http://itexpertvoice.com/home/troubleshooting-ipv6-on-windows-7-and-why-its-worth-the-bother/