You install Microsoft Windows Server 2003 Service Pack 1 (SP1) on a computer that is running Microsoft Internet Security and Acceleration (ISA) Server 2004, Standard Edition or Microsoft Internet Security and Acceleration (ISA) Server 2000. After you install the service pack, the ISA Server remote procedure call (RPC) filter blocks RPC traffic between networks.
RPC traffic between all other servers is not affected.
This problem does not occur with ISA Server 2004, Enterprise Edition.
This problem occurs because the ISA Server RPC filter is not compatible with the changes in the RPC protocol that are introduced by Windows Server 2003 SP1.
When you enable the ISA Server RPC filter, the RPC filter enforces strict compliance with a subset of the RPC protocol that is used by Microsoft Exchange Server MAPI communications. For more information about changes in the RPC protocol that are introduced by Windows Server 2003 SP1, click the following article number to view the article in the Microsoft Knowledge Base:
899148 Some firewalls may reject network traffic that originates from Windows Server 2003 Service Pack 1-based computers
ISA Server 2004, Standard Edition
Service pack information
To resolve this problem, install ISA Server 2004 Service Pack 1 (SP1). For more information about how to obtain the latest ISA Server 2004 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
891024 How to obtain the latest ISA Server 2004 service pack
ISA Server 2000
A supported update is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This update may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Internet Security and Acceleration Server 2000 or 2004 service pack that contains this update.
To install this update, you must have ISA Server 2000 Service Pack 2 installed.
You do not have to restart the computer after you install this update.
The update installer will prompt you to restart ISA services. You must restart ISA services.
Microsoft recommends that you disconnect from your Internet service provider when you install this update.
Update replacement information
This update does not replace any other updates.
The following file is available for download from the Microsoft Download Center:
Download the ISA 2000 RPC Update package now.
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.
The English version of this update 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. Date Time Version Size File name
12-Dec-2004 05:42 3.0.1200.410 61,944 Rpcfltr.dll
To work around this problem, disable the ISA Server RPC filter.
Note When you disable the ISA Server RPC filter, you also disable RPC protocol filtering of traffic that is processed by the ISA Server RPC publishing rules.
Microsoft has confirmed that this is a problem in Microsoft Internet Security and Acceleration Server 2000 and in Microsoft Internet Security and Acceleration Server 2004, Standard Edition.