Windows 7: Losing DNS?

Hi to all on the forum. Sorry my first post is a problem for you to look at! I have seen many posts along similar lines to my problem, but nothing exactly the same and no working answers!

I have a Win 2008 domain controller and various Windows 7 pcs (32 and 64bit, Pro and Ultimate), wired and wireless, plus a network printer and a couple of game consoles (PS3 and Wii). I have a router connected to broadband.

The server is on 192.168.1.1 and provides IP4 and IP6 addressing via DHCP for the rest of the network, except the router and printer which are hard-coded addresses (the router on .254).

Most of the network works perfectly all of the time. However, I have two machines that lose connectivity. One is a laptop that after a couple of hours, will no longer be able to access network resources. That one is wireless. The other is a desktop, wired via a switch, that will suffer the same loss of connectivity after waking from hibernation. Other machines cope with hibernation, etc, without losing connectivity.

The problem seems to relate to DNS. Once connectivity is lost, using mapped network drives or shared resources (such as the printer) by name is impossible (ie \\servername\sharename). However, using the IP address works fine (so I can remap a failed drive to \\192.168.1.1\sharename). Another test is using net view: net view servername fails with error 'System error 53 has occurred. The network path was not found.'; using net view 192.168.1.1 returns the full list of shared resources on the server. I can always use the internet - it seems to be only local names that are no longer resolved. Also, PINGing by name still works - so I can PING servername and get a reply.



The fact that shares can be used in this manner precludes security/permissions and firewalls. Renewing adaptor leases or disabling/re-enabling the adaptor does not cure the problem. Only a restart seems to work and I cannot keep restarting every couple of hours! This has only happened since moving to Windows 7. Previously, the network was all XP Pro machines and this never occurred.

My only guess so far is that the problem lie with IPv6 resolution. Internet and ping all use IPv4 so work fine; the internal network is 4 and 6 capable, but I don't know enough about IPv6 to fully diagnose that as the potential problem. Any help or ideas would be greatly appreciated.