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Consider the following scenario. You have a Windows domain on which Microsoft Internet Security and Acceleration (ISA) Server 2004 is configured as a firewall. You try to add to the domain a client computer that is running a 64-bit version of Windows Vista. However, you receive an "RPC Server unavailable" error message on the client computer. Additionally, the computer is not added to the domain.
Note This problem occurs primarily in a Microsoft Windows Small Business Server 2003 (Windows SBS) domain.
This problem occurs because 64-bit Windows Vista client computers add a third context element structure to a remote procedure call (RPC) bind call. However, the ISA Server RPC application filter drops this bind call as an incorrect RPC bind packet.
How to obtain the hotfix
On a computer that is running ISA Server 2004, Standard Edition and Microsoft Windows Small Business Server 2003, Premium Edition, obtain the hotfix from the Microsoft Download Center.
The following file is available for download from the Microsoft Download Center:
For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.
On a computer that is not running Windows Small Business Center 2003 but that is running ISA Server 2004, Standard Edition or ISA Server 2004, Enterprise Edition, apply hotfix 919621. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
919621 Description of the ISA Server 2004 hotfix package: May 31, 2006
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.