How to disable the Media Sensing feature for TCP/IP in Windows

On a Windows-based computer that uses TCP/IP, you can use the Media Sensing feat...

On a Windows-based computer that uses TCP/IP, you can use the Media Sensing feature to detect whether the network media are in a link state. Ethernet network adapters and hubs typically have a "link" light that indicates the connection status. This status is the same condition that Windows interprets as a link state. Whenever Windows detects a "down" state, it removes the bound protocols from that adapter until it is detected as "up" again. Sometimes, you may not want the network adapter to detect this state. You can set this configuration by modifying the registry.

Note 10B2 coaxial (RG-58) Ethernet cable is not a connection-based medium. Therefore, Windows does not try to detect a link state when this kind of cabling is used.

MORE INFORMATION

Important This section, method, or task contains steps that tell you how to modi...

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756  (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows

To prevent the network adapter from detecting a link state, follow these steps.

Note The NetBEUI protocol and the IPX protocol do not support Media Sensing.

1. Start Registry Editor.
2. Locate the following registry subkey:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
3. Add the following registry entry to the Parameters subkey:
   Name: DisableDHCPMediaSense
   Data type: REG_DWORD (Boolean)
   Value: 1
   Note This entry controls the behavior of Media Sensing. By default, Media Sensing events trigger a DHCP client to take an action. For example, when a connect event occurs, the client tries to obtain a lease. When a disconnect event occurs, the client may invalidate the interface and routes. If you set this value data to 1, DHCP clients and non-DHCP clients ignore Media Sensing events.
4. Restart the computer.

Note Microsoft Windows Server 2003 supports Media Sensing when it is used in a server cluster environment. By default, however, Media Sensing is disabled in a Windows Server 2003-based server cluster, and the DisableDHCPMediaSense registry entry has no effect. In Windows Server 2003 Service Pack 1 (SP1), the DisableClusSvcMediaSense registry entry was introduced. You can use this registry entry to enable Media Sensing on the Windows Server 2003-based nodes of a server cluster. The details of the DisableClusSvcMediaSense registry entry are as follows:

Key: HKEY_LOCAL_MACHINE\Cluster\Parameters
Name: DisableClusSvcMediaSense
Data type: REG_DWORD (Boolean)
Default value: 0

By default, the DisableClusSvcMediaSense entry is set to 0. When this entry is set to 0, Media Sensing is disabled. If you set the DisableClusSvcMediaSense entry to 1, you can use the DisableDHCPMediaSense entry to enable Media Sensing. This behavior matches the behavior of a Microsoft Windows 2000 Server cluster environment.

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APPLIES TO

 

• Microsoft Windows Server 2003, Standard Edition (32-bit x86)
• Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
• Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
• Microsoft Windows Server 2003, Web Edition
• Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
• Microsoft Windows XP Professional 64-Bit Edition (Itanium)
• Microsoft Windows XP Home Edition
• Microsoft Windows XP Media Center Edition 2004
• Microsoft Windows XP Professional
• Microsoft Windows XP Tablet PC Edition
• Microsoft Windows 2000 Server
• Microsoft Windows 2000 Advanced Server
• Microsoft Windows 2000 Datacenter Server
• Microsoft Windows 2000 Professional Edition
• Microsoft Systems Management Server 2003

“Media Sensing” is a feature in recent versions of Microsoft Windows operating systems including Windows 2000, Windows XP and Windows Vista. This feature automatically detects whether the network media are in a “link” state, in a Windows machine with TCP/IP protocols. With Media Sense feature,  Windows senses a link state as UP or DOWN based on the link availability. Ethernet network adapters and hubs typically have a “link” light that indicates the connection status. This status is the same condition that Windows interprets as a link state. When Windows detects a “down” state, it removes the bound protocols from that adapter until it is detected as “up” again. When the network cable is disconnected from the Ethernet adapter, due to the action of Media Sensing feature, Windows shows a message like a “Network disconnected” icon on the Windows Taskbar and the ‘ipconfig’ command shows a “Media State …: Cable disconnected” message and disables the entire network protocol stack.

Media Sensing feature is enabled by default in Windows except Windows Server 2003. However, in instances where you do not want Windows to sense link status (very unlikely) in which case, you can disable the Media Sensing feature from Windows Registry.

To prevent the network adapter from detecting a link state,ie disable the Media Sensing feature in Windows, follow these steps.

• Start the Windows registry editor by clicking Start, then, Run, and then entering regedit.
• You’ll need to provide administrative confirmation if User Account Control(UAC) is turned on(If you are using Windows Vista).
• Navigate to the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

• From the Edit menu select New -> DWORD value.
• Enter a name of DisableDHCPMediaSense and press Enter.
• Double click the new value and set to 1.(Note: Setting “1″ will disable Media Sensing feature.If you to enable Media Sensing feature at a later time, set it “0″ or simply delete the this key.)
• Click OK and exit Windows Registry Editor.
• Restart your computer for the changes to take effect.

Note:

• This registry tweak applies to Windows Server 2008, Windows Vista, Windows XP, Windows Server 2003 (if enabled) and Windows 2000.
• 10b2 or coaxial (RG-58) Ethernet cable is not a connection-based media. Because of this, Windows does not attempt to detect a “connect” state if this type of cabling is used.

Warning:

Modifying the Windows registry can cause serious damage to your Windows Operating System.It is better to backup your Windows registry data before making any changes. Tomstricks.com is not responsible for any changes you may make to your system.

Disable Media Sensing

What is "Media Sensing"?
"Media Sensing" is a new feature in recent versions of Microsoft Windows that not many people aware of. In a Windows machine with Tcp/ip protocols, this feature automatically detects whether the network media are in a "link" state. Ethernet network adapters and hubs typically have a "link" light that indicates the connection status. Whenever Windows detects a "down" state, for example, cable unplugged, it automatically removes the bound protocols from that adapter until the adapter appears to be back up again.
Why disable?
In some situations, this feature also introduces issues. And again, because not many people aware of this feature, it is hard to find out what it really is and how to change it.
For example, some Windows users might have network card(s) with unstable link light. In this case, the link light on the network adapter is not reporting the status correctly even though the network card is still functioning. Windows would detect the changes of network status every once in a while, causing random and un-necessary protocol changes.
Another example, on some computers with multiple network adapters and multiple networks, and the users or administrators want to keep the networks completely seperate; Howerver, once an adapter goes down, Windows detects the failure and re-configure the protocols and might forward the network traffic to other adapters.
Little more?
This "Media Sense" feature basically updates the routing table depending on the new status of network adapters. With this, it is very much impossible to manually manage the network traffic since Windows keeps changing the routes automatically. Either you're in one of the above situations or you want to manage the network manually, follow the below procedures to disable this feature.
Use this trick at your own risk.
Here's how to disable the Media Sensing:

Open Registry Editor (Start >> Run >> type in "regedit" and press Enter)

Expand to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters

On the right panel, right-click and select "New" >> "DWORD Value"

Rename the new value to "DisableDHCPMediaSense"

Double-click on the new value "DisableDHCPMediaSense" and edit the "Value Data" to "1"

Click OK and exit the registry editor, then restart Windows 

Media Sense is a feature of Windows XP/2000 that automatically detects if a network cable is plugged into the Network Interface Card (NIC) and a cable modem or router.
When the network cable is disconnected, Windows will display a message similar to "Network cable is unplugged” on the TaskBar and can also be seen as "Media State ...: Cable Disconnected" when using the 'ipconfig' command within an MS-DOS prompt. Once Windows detects that the network cable has been disconnect, it disables the entire network protocol stack. Media Sense was designed to enable the network protocol stack once the network cable is plugged back into the NIC or cable modem/router, but in some instances, would not recognize the network cable and keep the network protocol stack disabled. Basically, this means that your computer cannot establish a connection to the Internet because Windows Media Sense has failed.
Below are links that discuss how to disable the Media Sense feature. However it is important to note a few things prior to taking this action. Microsoft has quoted the following warning:
Administering Windows Vista Security: The Big Surprises
There are some side effects of disabling the "Media Sensing" feature. For example, if you have a machine with two network adapters, and you have the "Media Sensing" feature enabled, if one network adapter does not work, it is unbound, and associated routes are removed so that all traffic goes through the other network adapter (assuming a default gateway is there). Also, if you are a roaming (portable) user, the "Media Sensing" feature is what provides the ability to connect to any network and have everything work, without restarting, release and renewing, and so on. After disabling Media Sense and restarting, Windows still shows the "Network Disconnected" icon on the TaskBar and the 'ipconfig' command still shows a "Media State .....: Cable Disconnected" message when the cable is disconnected. However, the Network Interface is bound to TCP/IP and you can verify this by looking at the route table --you can use the "route print" command-- which shows the interface IP address (you are also able to ping the IP address assigned to the NIC).”
The links for more information about Media Sense can be found here:
Microsoft Knowledge Base #239924
Microsoft Knowldge Base Supplemental Information