When you disconnect and then reconnect a network adaptor on a Windows XP-based computer, the IPsec policy is not applied for two to three seconds after the network adaptor is reinitialized

You may experience the following problem on a Microsoft Windows XP-based computer where a network adaptor uses the Internet Protocol security (IPsec) policy to restrict traffic to and from the computer. When you disconnect and then reconnect the network adaptor, the policy is not applied for two to three seconds after the network adaptor is reinitialized. Traffic that typically would be blocked by the IPSec policy may not be blocked.

This problem occurs because the network adaptor may initialize before the IPsec policy is applied. This problem occurs under certain conditions when you reinitialize an existing network adaptor.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

This hotfix requires Windows XP Service Pack 2.

Restart requirement

You must restart the 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 tool in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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.

This problem may occur only when you set the IP filter destination address to A specific IP Address in the Filter Properties dialog box. This problem does not occur when you set the IP filter destination address to My IP Address in the Filter Properties dialog box.

After you install the hotfix, add the EnablePnpFiltering registry value. Then, set the value to 1. To do this, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. In the left pane, locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IPSec
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type EnablePnpFiltering, and then press ENTER.
5. Double-click EnablePnpFiltering, type 1 in the Value data box, and then click OK.
6. Quit Registry Editor.
7. Restart the computer.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: