The RPC binding order is not correct
[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at https://go.microsoft.com/fwlink/?linkid=34707.]
Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine the remote procedure call (RPC) binding order in use by the Exchange Server computer:
HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Exchange Provider\Rpc_Svr_Binding_Order
If the Exchange Server Analyzer finds the value for Rpc_Svr_Binding_Order does not start with ncacn_ip_tcp, an error is displayed.
The Rpc_Svr_Binding_Order registry entry is created when you install Exchange Server on a computer. This entry determines the protocol sequence that is used for server-to-server RPC communications.
By default, the Rpc_Svr_Binding_Order entry contains the following value data:
ncacn_ip_tcp,ncacn_spx,ncacn_vns_spp
Note
Additional values may be in the string if other protocols are also installed on the Exchange Server computer.
This entry specifies the order in which Exchange Server tries network communication protocols for RPC communications with other servers. For example, because TCP/IP is specified first, Exchange Server tries to communicate with other servers using RPC over TCP/IP first, before trying RPC over other protocols.
It is recommended that you not change the RPC binding order from the default value. If the default value is changed, you may encounter problems during server or service startup or with server-to-server communications.
Important
This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.
To correct this error
Open a registry editor such as Regedit.exe or Regedt32.exe.
Navigate to: HKLM\Software\Microsoft\Exchange\Exchange Provider
In the right pane, double-click Rpc_Svr_Binding_Order.
In the Value data dialog box, type ncacn_ip_tcp,ncacn_spx,ncacn_vns_spp.
Click OK, and then close the registry editor.
Restart all Exchange Server services, or restart the Exchange Server computer for the change to take effect.
Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).
For more information about the RPC binding order, see the Knowledge Base article 325930, "How to troubleshoot connectivity issues that are caused by RPC client protocol registry entries" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=325930).