You receive a "The remote procedure call failed" error message and RPC route publishing is not permitted in ISA Server 2004 or Forefront Threat Management Gateway or Medium Business Edition & Windows Essential Business Server 2008

RPC route publishing may not be permitted by a computer that is running Microsoft Internet Security and Acceleration (ISA) Server 2004, by Microsoft Forefront Threat Management Gateway, Medium Business Edition, or by Windows Essential Business Server 2008. Additionally, users may receive the following error message:

This issue occurs because more than one protocol definition is selected for the same RPC server in ISA Server 2004, in Microsoft Forefront Threat Management Gateway, Medium Business Edition, or in Windows Essential Business Server 2008. The following procedures occur if the RPC traffic in ISA Server is split between different RPC protocol definitions:

• The firewall tries to match all RPC traffic to the original RPC protocol definition.
• The firewall does not permit traffic that matches the other protocol definitions.

To resolve this issue, create only one protocol definition for each published server. For example, to publish an RPC server in route scenario, create a protocol definition that includes all the server's interfaces. To do this, follow these steps:

1. Click Start, point to Programs, point to Microsoft ISA Server, and then click ISA Server Management.
2. In the left pane, click Firewall Policy.
3. In the right pane, click the Toolbox tab, and then expand Protocols.
4. Under Protocols, click New, and then click RPC Protocol.
5. On the New Protocol Definition Wizard page, type RPC Server, and then click Next.
6. On the Select Server page, type the name of the RPC server in the Server Name box, and then click Next.
7. Click to select the check boxes for all the available interfaces that belong to the published RPC server on the Server Interfaces page, and then click Next.
8. Click Finish.
9. In the middle pane, click Apply to save the changes and to update the firewall policy.
   
   Note The RPC Server protocol definition that is listed on the Protocols menu in the User-Defined folder should be used for the corresponding publishing rule.