IPsec traffic may be blocked when a computer that is running Windows 7 or Windows Server 2008 R2 is behind HLB equipment

After you install this hotfix, you can configure the zombie value manually by configuring the IkeNumEstablishedForInitialQuery registry entry. This enables you to configure a larger value to support the number of concurrent connections that are expected from a single IP address. The recommended value should be at least double the number of unique peers that you expect to connect to a particular server. For example, if you expect 1,000 SAs the recommended value should be at least 2,000.

To enable the new value that is configured in the IkeNumEstablishedForInitialQuery registry entry for the IPsec module, run the following commands, or restart the computer. As soon as all steps are performed, the computer is ready to participate in an HLB and IPsec-supported network.

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 the problem described in this article. 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:

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

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

To apply this hotfix, you must be running one of the following operating systems:

• Windows 7
• Windows 7 Service Pack 1 (SP1)
• Windows Server 2008 R2
• Windows Server 2008 R2 Service Pack 1 (SP1)

For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

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 How to back up and restore the registry in Windows

After you apply the hotfix package, to have us configure the zombie value for you, go to the "Fix it for me" section. If you prefer to configure the zombie value yourself, go to the "Let me fix it myself" section.

Fix it for me

To configure the zombie value automatically, click the Fix it button or link. Then click Run in the File Download dialog box, and follow the steps in the Fix it wizard.

Notes

• Install the hotfix in the "Hotfix download available" section at the top of this Knowledge Base article before you run this Fix it solution.
• This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
• If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.

Let me fix it myself

To configure the zombie value, follow these steps to create the necessary registry entries:

1. Click Start, type regedit in the Search programs and files box, and then press ENTER.
   If you are prompted for an administrator password, type the password. If you are prompted for confirmation, provide confirmation.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\IKEEXT\Parameters
3. On the Edit menu, point to New, and then click DWORD (32-bit) Value.
4. Type IkeNumEstablishedForInitialQuery, and then press ENTER.
5. Right-click IkeNumEstablishedForInitialQuery, and then click Modify.
6. In the Value data box, type 0000c350, and then click OK.
7. Exit Registry Editor.

Did this fix the problem?

• Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support.
• We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me" blog or send us an email.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 7 and Windows Server 2008 R2 file information notes

• The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
  

  Version	Product	Milestone	Service branch
  6.1.760 0.16xxx	Windows 7 and Windows Server 2008 R2	RTM	GDR
  6.1.760 0.21xxx	Windows 7 and Windows Server 2008 R2	RTM	LDR
  6.1.760 1.17xxx	Windows 7 and Windows Server 2008 R2	SP1	GDR
  6.1.760 1.21xxx	Windows 7 and Windows Server 2008 R2	SP1	LDR

• GDR service branches contain only those fixes that are widely released to address widespread, extremely important issues. LDR service branches contain hotfixes in addition to widely released fixes.
• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows 7

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2