strange issue came up for me recently, my notebook running Windows 7, stopped to be able to connect to CIFS shares. I keep getting that the “network is not reacheable” error from Windows. Networking wise, it’s incorrect as I can ping the device and I can access the web services on the device.
Some research pointed me to the proliferation of the 6to4 adapters in Windows. These adapters help to route IPv6 over IPv4, and for some reason, I’ve got hundreds of these adapters in my system.
All I had to do is to remove them by disabling IPv6, and the problem got resolved. No root cause here yet, but at least there’s the fix.
So, go to http://support.microsoft.com/kb/929852 and apply Fix #50409 & #50412. Both will need a reboot each time, and then my problem was resolved.