Windows 7 and Vista Network Problems

Vista and Windows 7 laptops may have problems with "Unidentified Networks" and broken network connections in a home network. This article discusses the solution and it deals with multiple issues, including network cards, power-settings, DHCP resolution, and disabling IPV6. Also information on the Teredo Tunneling Pseudo Interface.

Note: This article was originally written for Vista, but Windows 7 has the same problem, with the same solution.

Symptoms:

• Windows 7 / Vista report an "Unidentified Network" error.
• Network Discovery and File Sharing may mysteriously turn off.
• You may loose both your intranet and Internet network connections.
• Other wired desktop computers may temporarily loose their network connections.
  
  
• The entire home network may "crash" when a laptop connects to the Wireless.
• Laptops may have recently woke from sleep mode.
  
• After several minutes, the desktop computers may recover and re-establish their connections.
  
  
• You likely have a LinkSys WRT110 Router; other routers are implicated.
  
• The laptop has an Intel 3945ABG Wireless Network adapter or related cousins; or a Atheros AR5007 Wifi Adapter (Readers suggest other network cards are also a problem -- indicating this is really a problem with the Router).
  

Rebooting may restore the connection, or fiddling within the Network control panel may coax the connection back online.

The Network control panel will look similar to this:

With Windows Vista, Microsoft confirmed several bugs in this area. According to Microsoft and other sources, this problem occurs on machines (laptops) with multiple network cards (a wired and wireless connection). Links below detail the issues.


The following steps can be applied in any order and is written from a wireless laptop's point of view.

I recommend applying these changes to all wired and wireless Windows 7 and Vista computers on the local network. There are several areas that need your attention in order to complete the task.

Do not use these steps for Windows XP machines, which may also reside on the same network.


1. Update your wireless drivers to the latest version

There are known bugs with IPV6 processing on Intel network adapters and it is always a good idea to upgrade to the latest versions. Unfortunately, those of us who upgraded to Windows 7, may not find appropriate x64 drivers. Resolving this will take research and the details are not discussed here.

If the control panel shows a default Microsoft Network drivers; these should be upgraded to the vendor's real drivers. Contact your OEM vendor or check your shipping manifest for the correct network card. For laptops, the Wired and Wireless will use different drivers; see the Intel links below.

For my machine, Intel released a new Wireless Notebook Adapter drivers for the 3945ABG, 4965AGN, and 51x card-series. Your adapters may be different.

• Intel Pro/Wireless 3945ABG
  (Version 13.0.0.107 2010.01.07 - Drivers + Utils - Recommended)
  
  
• Intel Pro/Wireless 3945ABG
  (Version 13.0.0.107 2009.10.21 - Drivers only)

Wired driver:

• Marvell 88E8040 Ethernet Controller (ver 11.23.2.3 2009.11.09)

Note: Microsoft Update periodically updates drivers, but I still recommend using the vendor's (usually Intel) latest versions. See this Intel link for an index of all versions: Link

See this article's last step for information on the related Teredo Tunneling problem.

2. Upgrade your Router's Firmware

I recommend upgrading your home router's BIOS / Firmware to the latest version. See this Keyliner article: Upgrade Linksys WRT110 Firmware or check the Vendor's site for details.

You can do this step after completing the rest of the recommendations in this article. Linksys routers have had some bug fixes in this area and I've moved this higher in the list. This is admittedly a pain.


3. Set Power Settings keeping the network adapter at full power

a. Click the System Tray Battery Icon, Choose "More Power Options"
b. Under "Balanced", click "Change Plan Settings"
c. Click "Change Advanced Power Settings"
d. Tunnel to "Wireless Adapter Settings, Power Saving Mode"
e. Change "On Battery" to "Maximum Performance"; Click OK to save
f. Make the same change in the "Power Saver" profile.



See Microsoft Article http://support.microsoft.com/kb/928152 for details on this issue. Obviously, this affects battery life.


4. Disable the DHCP Broadcast Flag

Edit the Registry and modify a DHCP Broadcast flag setting. This does not disable the feature but it does change the order on how the DHCP addresses are discovered. As dangerous as this sounds, it is benign, only changing how DHCP is searched. These instructions assume you know how to edit the registry; if not, please talk with a knowledgeable friend.

a. Start, Run "Regedit"
See this article for instructions on exposing the RUN command for both Windows 7 and Vista.

b. Tunnel to

HKey_Local_Machine\System\CurrentControlSet\Services\TCPIP\Parameters\Interfaces

c. In the key you will find multiple {GUID}'s

Within each populated key,
select Edit, New,
Click DWORD-32 Value
Create/name "DhcpConnEnableBcastFlagToggle"
Press Enter

d. Double-click the newly-added value, set value to (Hex) 1 (one).



e. Make similar changes to other GUID's.

f. Leave Regedit open for the next step.

For reference: See Microsoft article: http://support.microsoft.com/kb/928233/en-us for details. Note they are vague by saying "click the GUID that corresponds with your network adapter." They do not explain how to tell which GUID belongs to your wireless. It is safe to make this modification for all network adapters.


5. Disable TCPIP6

Win7 / Vista supports the new IPV6 IP Addressing scheme, which is great, except the entire world still uses the old IPV4 standard. There appears to be conflicts between this new protocol and most home routers. Here is how you can safely disable it. Note: In order to properly disable this protocol, you need to make changes in the Control Panel *and* in the registry.

---

This is the fix that most likely solves
the crashed router problem

---

Still in Regedit, continue with these steps

a. Tunnel to
HKLM\System\CurrentControlSet\Services\TCPIP6\Parameters
* Note: this is not the previously-edited TCPIP key *

b. Create a new DWORD-32 value:

"DisabledComponents"
Set the value equal to (hex) "ffffffff" (8-f's: 4294967295)

c. Close regedit.

This change is only required one time in the registry, regardless of the number of network adapters. Detailed reference on IPv6, see this Microsoft article: http://www.microsoft.com/technet/network/ipv6/ipv6faq.mspx.

Microsoft does have one warning about disabling this protocol, which you can probably safely ignore: "If you disable IPv6, you will not be able to use Windows Meeting Space or any application that relies on the Windows Peer-to-Peer Networking platform or the Teredo transition technology." Update: Windows 7 "HomeGroups" will not work if IPV-6 is disabled; however, regular peer-to-peer networking works; if you don't use Home Groups, this is still a good fix to apply (2010.01.29 - trw)

This does not mean it hurts peer-to-peer networking; which works perfectly well when IPv6 is disabled. I suspect this warning only applies to .001% of the users out there and I have seen no issues with this change.


6. Disable IPV6 on the Cards

a. Other-mouse-click, Network (Neighborhood), select "Properties"
See this article for instructions on exposing the Network Desktop icon.

b. Windows 7 users: Click on left, "Change adapter settings"
Vista users: Click on left, "Manage Network Connections"

c. From the displayed adapter list, other-mouse-click your (wireless) Network Adapter, select "Properties"

d. Uncheck [ ] "Internet Protocol Version 6 (TCP/IPv6)" (be sure to leave IPV4 checked)

e. Do the same for *all* other Network adapters, even if not connected.

7. Reboot for these changes to take effect.
You must reboot before proceeding to the next step.

7. Teredo Tunneling
If you are using a newer Intel Wireless driver, open the Control Panel, "Device Manager", and scroll to the Network Adapter section.

You may see a failed "Teredo Tunneling" yellow-bang icon.

• "Teredo Tunneling Pseudo-Interface
  (yellow-bang and 'This device cannot start. (Code 10)').

This is a protocol allowing IPV6 traffic to tunnel over IPV4 routers. Since 99.9% of all home routers cannot handle IPV6, this error is not a concern and it can be ignored or disabled by following this recommendation:

a. In Device Manager, Network, other-mouse-click "Teredo Tunnelling Pseudo Interface"; choose "Disable".

This assumes you have disabled IPV6 in the steps above.


Conclusions

On my computer, these changes solved my networking problems. With the Powersaving, DHCP, and IPV6 changes, the network connections have been flawless.

These steps will not solve the problem where a laptop is on one wireless network, goes to sleep and wakes on another (I am still looking for a solution to this).

Admittedly, disabling powersave features and other registry changes are not elegant solutions.

Your comments and experiences on this are welcome. Please leave unregistered, anonymous comments below.