You cannot establish an IPsec connection between a Linux operating system and a Windows Vista operating system when you initiate the connection from the Linux operating system

Consider the following scenario. You use Windows Vista Local Security Policy on a Windows Vista-based computer. Or, you use the new Windows Firewall with Advanced Security on a Windows Vista-based computer. You try to initiate an Internet Protocol Security (IPsec) connection from a Linux-based computer to the Windows Vista-based computer. In this scenario, you cannot establish the connection.

Notes

• If you initiate the IPsec connection from the Windows Vista side, the connection is established correctly.
• Windows XP and Windows Server 2003 work correctly with the Linux operating system in this environment.

In IPsec negotiation for transform proposal of the combination where Authentication Header (AH) and Encapsulating Security Payload (ESP) are used for securing the same packet (AH+ESP), Windows Vista switches the order and replaces the packet with ESP+AH. This behavior breaks the negotiation. In this case, when you initiate the IPsec connection from a Linux-based computer, the Linux operating system proposes that the IPsec security format is AH+ESP. Therefore, the connection cannot be established.

To work around this issue, modify the policy to use ESP or to use AH.

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

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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.

Windows Vista, x86-based versions

Windows Vista, x64-based versions

Windows Vista, Itanium-based versions

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

For more information about security policy settings for Windows Vista, visit the following Microsoft Web site: For more information about Windows Firewall with Advanced Security and IPsec, visit the following Microsoft Web sites: The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.