Microsoft KB Archive/818635

= Your portable computer cannot renew its IP address from a DHCP server after you remove the computer from a docking station =

Article ID: 818635

Article Last Modified on 10/26/2006

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APPLIES TO


 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Service Pack 4
 * Microsoft Windows 2000 Advanced Server

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Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

This article applies only to Microsoft Windows 2000 SP4 and does not apply to other versions of Windows 2000.



SYMPTOMS
A portable computer may not be able to renew its Internet Protocol (IP) address from a Dynamic Host Configuration Protocol (DHCP) server after you remove the computer from a docking station or from a port replicator. Additionally, no errors are recorded in the system log, and this problem still occurs after you disable and then re-enable the network adapter.



CAUSE
This problem occurs because the computer cannot reach the DHCP server. Windows 2000 uses the Media Sense feature to remove protocols that are bound to a network adapter that is sensed as &quot;down&quot; or &quot;disconnected.&quot; In the scenario that is described in the &quot;Symptoms&quot; section, the Internet Control Message Protocol (ICMP) send request returns a Pending status, Media Sense removes the TCP/IP protocol, and the network adapter is not detected because there are no protocols bound to the network adapter.



Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites
No prerequisites are required.

Restart requirement
You must restart your computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



WORKAROUND
To work around this problem, prevent your network adapter from detecting the link state by modifying the registry to disable the Media Sense feature for TCP/IP. To do this, follow these steps.

Note NetBIOS Extended User Interface (NetBEUI) and Internetwork Packet Exchange (IPX) do not recognize the Media Sense feature.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.  Click Start, and then click Run. In the Open box, type regedit, and then click OK. Locate and then click the following registry subkey:

 On the Edit menu, point to New, and then click DWORD Value Type DisableDHCPMediaSense as the name of the new entry, and then press ENTER.</li> Double-click the new DisableDHCPMediaSense entry, type 1 in the Value data box, and then click OK.</li> Quit Registry Editor, and then restart your computer.</li></ol>

Note The DisableDHCPMediaSense value controls DHCP Media Sense behavior. If you set this value to 1, DHCP clients and non-DHCP clients ignore Media Sense events from the network adapter. By default, Media Sense events trigger the client to take an action, such as to try to obtain a lease when a connect event occurs, or to invalidate the network adapter and routes when a disconnect event occurs. For more information about how to disable Media Sense for TCP/IP, click the following article number to view the article in the Microsoft Knowledge Base:

239924 How to disable the &quot;Media Sensing&quot; feature for TCP/IP in Windows

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MORE INFORMATION
For more information about how hotfix packages are named, click the following article number to view the article in the Microsoft Knowledge Base:

816915 New naming schema for Microsoft Windows software update packages

For more information about the terminology that is used in this article, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional query words: dock station docking port replicator eject pc dhcp ip renew notebook laptop portable

Keywords: kbhotfixserver kbbug kbfix kbqfe kbwin2000presp5fix KB818635

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