Windows 7: lose wifi connectivity, GP's fail and then logon failure

Hello,

I have a network with several hundred laptops, I have mostly XP machines that are all working fine. Recently I have rolled out 2 new models of laptop (80 or so) running Win 7 Pro, everything works fine after imaging I run a gpupdate, policies come down without errors and everthing is fine.

After what seems like random periods of time, the Win 7 laptops (always a few, but never all of them) stop logging on users and I get the error: "There are currently no servers availiable to service the logon request"

So I go into the logs on the laptops, I see connectivity failures, at this stage it's worth pointing out that one type of laptop has an Intel Wifi adapter and the other an Atheros, one is a HP and the other a Lenovo and none of the laptops have virtually any hardware in common. Our wireless is a managed CISCO solution and does not experience any issues at the time. There are often XP machines (same type of laptops) along side the Windows 7 ones and they are working away fine.

When the connectivity issue occurs on the Windows 7 client it does not recover and we then have to do a gpupdate over a LAN cable, the policies are again applied (no errors) and after a reboot the wireless is back and working and users can logon fine.

I have tried many things that I have read on the web without success, I'll give you a short list of what I've have tried:



-I have updated drivers
-I have the latest Windows 7 updates
-IPv6 is now turned off
-WINS is now off too (don't need it anyway)
-GpNetworkStartTimeoutPolicyValue added @ a delay of 60 seconds.
-Local printer installed instead of network GP install incase of dodgy Windows 7 printer driver.
-Disable Microsoft virtual Wifi (in device manager)
-Power saving turned off
-disabled and re-enabled the adapter
-changed network types from WPA2 to a WPA-PSK and manually specified key on client, connectivity still fails and client forgets key.

I have also tried the usual restarts etc... and am fast running out of idea's, so I'm really hopeful someone might have some suggestions?

Any help would be very appriciated..
thanks.

When the problem presents, have you inspected the IP address information that the problem laptops are using at that time. Is it possible that there is another DHCP source available on the network that may be providing erroneous information, specifically DNS server addresses. The error that you mentioned is not uncommon when name resolution is looking to the wrong DNS server, perhaps a wireless router (rogue DHCP) that is responding to DHCP solicitations.

After reading a Technet thread about the same problem only one solution seems to be working. These settings have already fixed a very similar problem once before so I'm reposting this from my own post from a few weeks ago.

There are many other works arounds for this problem in the link below but this one seems to be working the best. You need to re-enable IPv6 and go back to using WPA-2 and AES encryption.

First start an administrator console by entering cmd into the searchbox on the start menu, right click the little icon and choose "run as administrator".

In the console enter the following commands to change the MTU:

Type into command window "netsh interface ipv4 show interfaces" without the quotes. Take note of the id number of the wireless interface.

Then to change to mtu 1460 use the following command.

"netsh interface ipv4 set subinterface id mtu=1460 store=persistent"

Source> Windows 7: Cannot access *some* folders on a Network Drive(NAS) via wireless connection

Hello Chev65,

I'll give that a try and see how I get on, out of interest why do I need to re-enable IPv6?

MTU size on the laptop Wifi interface I'm looking at now is set to 1500, is this simply to large?

Thanks for your help, cheers!

Yes the MTU size difference is what's causing this problem to occur, the link above explains more about this.

IPv6 is required for many other system networking functions. Most people do not realize this and mistakingly disable it.


The Argument against Disabling IPv6
It is unfortunate that some organizations disable IPv6 on their computers running Windows Vista or Windows Server 2008, where it is installed and enabled by default. Many disable IPv6-based on the assumption that they are not running any applications or services that use it. Others might disable it because of a misperception that having both IPv4 and IPv6 enabled effectively doubles their DNS and Web traffic. This is not true.
From Microsoft's perspective, IPv6 is a mandatory part of the Windows operating system and it is enabled and included in standard Windows service and application testing during the operating system development process. Because Windows was designed specifically with IPv6 present, Microsoft does not perform any testing to determine the effects of disabling IPv6. If IPv6 is disabled on Windows Vista, Windows Server 2008, or later versions, some components will not function. Moreover, applications that you might not think are using IPv6—such as Remote Assistance, HomeGroup, DirectAccess, and Windows Mail—could be.
Therefore, Microsoft recommends that you leave IPv6 enabled, even if you do not have an IPv6-enabled network, either native or tunneled. By leaving IPv6 enabled, you do not disable IPv6-only applications and services (for example, HomeGroup in Windows 7 and DirectAccess in Windows 7 and Windows Server 2008 R2 are IPv6-only) and your hosts can take advantage of IPv6-enhanced connectivity.

Read more. http://technet.microsoft.com/en-us/m....cableguy.aspx

Thanks very much for your help chev65, I have applied 1460 as the MTU size to a large group of Lenovo laptops (Windows 7 Pro) and am now waiting to see what happens. I've been reading a little more on the MTU size and note that it used to capped at 1300 wich I assume our XP computers are still, so I'm feeling increasingly confident about this....

Well been almost a week and changing the mtu size setting has certianly had some impact, I have so far seen 3x windows 7 laptops with the "There are currently no servers availiable to service the logon request" problem. This is so much better as I was seeing 3 or 4 at a time before...


I'm not convinced that the problem is totaly resolved however, but it's much, much better...

Thanks for the help so far...

Try this thread it may help you:
Command lines to solve most of the network problems

Thats about all I could find on this problem, there are a few other suggestions that might help in the link below like turning down the NTLM levels or updating the routers firmware which has also helped people to fix this problem.

Unfortuneately I can't test this out myself.

Source> Windows 7: Cannot access *some* folders on a Network Drive(NAS) via wireless connection

Yes I might try the NTLM fix if I have no luck, interestingly I have applied the MTU size fix to both models. One of them has not had the issue since, but this model also had all the other things I mentiod in my origional post still configured in it's image. So something else there is also the problem, I may have to back track one at a time until I find the other issue.

Wireless in Windows 7 has really been nothing but pain for me.... Hopefully SP1 might help with some of the issues.