You cannot assign a static IP address for client computers in a site-to-site VPN connection in Microsoft Internet Security and Acceleration Server 2004

If you configure a site-to-site VPN connection by using Microsoft Internet Security and Acceleration (ISA) Server 2004, you cannot assign a static IP address for the calling or answering computer that is making the connection.

Service pack information

To resolve this problem, obtain the latest service pack for Internet Security and Acceleration Server 2004. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

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

ISA Server 2004, Enterprise Edition

No prerequisites are required to install this hotfix.

ISA Server 2004, Standard Edition

You must install Microsoft ISA Server 2004, Standard Edition, Service Pack 1 before you install this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix. However, you must restart the Microsoft Firewall service.

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.

ISA Server 2004, Enterprise Edition

ISA Server 2004, Standard Edition

Microsoft has confirmed that this is a problem in ISA Server 2004. This problem was first corrected in Internet Security and Acceleration Server 2004 Service Pack 2.

In a branch office scenario, branch offices are connected by using an ISA Server 2004 site-to-site VPN connection. ISA Server 2004 assigns the IP address to the calling and answering computers that are making the connection. These assignments are taken from the pool of IP addresses that ISA Server 2004 manages. The IP address that is assigned is chosen at random. Additionally, you cannot receive a static IP address for either of the computers that are making the connection. However, if you want to use network monitoring tools to verify the status of the calling or answering computer, you must have a known static IP address.

You can set static IP addresses for the calling and answering computers that are making the VPN connection. You can set these static IP addresses in the Routing and Remote Access service configuration. However, when ISA Server 2004 starts, it overwrites the Routing and Remote Access configuration and sets the ISA Server 2004 VPN configuration. After you apply this hotfix, ISA Server 2004 does not overwrite the IP address that is configured in Routing and Remote Access. When a static IP address is set in Routing and Remote Access, ISA Server 2004 also does not overwrite the DNS settings.

However, ISA Server 2004 does not validate the static IP address that is set in Routing and Remote Access. ISA Server 2004 does not verify that the static IP address is not included in the IP address pool. Additionally, ISA Server 2004 does not verify that the static IP address is not assigned to more than one connection. You must manually validate such criterion.

For more information about how to set up VPN connections in ISA Server 2004, visit the following Microsoft Web sites: For more information about how to install ISA Server 2004 hotfixes and updates, click the following article number to view the article in the Microsoft Knowledge Base: