How to Disable Media Sense for TCP/IP in Windows 2000

ID: Q239924

The information in this article applies to:

Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Datacenter Server
Microsoft Windows 2000 Professional
Microsoft Windows 2000 Server

SUMMARY

Windows 2000 contains the "Media Sensing" feature. You may use this feature on a Windows 2000-based computer using Transmission Control Protocol/Internet Protocol (TCP/IP) to detect whether or not your network media is in a "link state". A "link state" is defined as the physical media connecting or inserting itself on the network. For example, assuming a 10bt or 100bt physical media, Ethernet network adapters and hubs typically have a "link" light to indicate the current connection status. This is the same condition in which Windows 2000 can detect a link. Whenever Windows 2000 detects a "down" state on the media, it removes the bound protocols from that adapter until it is detected as "up" again. There may be situations where you may not want your network adapter to detect this state, and you can configure this by editing the registry.

NOTE: 10b2 or coaxial (RG-58) Ethernet cable is not a connection-based media. Because of this, Windows 2000 does not attempt to detect a "connect" state if this type of cabling is used.

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).
To prevent your network adapter from detecting the link state:

NOTE: NetBEUI and IPX do not recognize Media Sense.

Use Registry Editor (Regedt32.exe) to view the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
Add the following registry value:
Value Name: DisableDHCPMediaSense
Data Type: REG_DWORD
Value: 0=Disabled 1=Enabled

Restart your computer.

NOTE: 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.

Additional query words:

Keywords : kbnetwork kbtool
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbhowto