Article ID: 163576 - Last Review: October 28, 2006 - Revision: 3.6

XGEN: Changing the RPC Binding Order

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SUMMARY

How Exchange Server Uses RPC

Exchange Server uses remote procedure call (RPC) built into Microsoft Windows NT to establish connections among the Exchange Server processes, such as connections between Exchange Server message transfer agents (MTAs), and to connect Exchange Clients and Exchange Server computers in the network. Exchange Server can use RPC over named pipes, TCP/IP, NetBIOS, and IPX/SPX. When it uses RPC, Exchange Server proceeds through a list of those protocols and tries to establish RPC binding. The preference order of the transports is defined by the RPC Binding Order, which by default is: local RPC, TCP/IP, SPX, named pipes, and then NetBIOS (in order of preference).
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Changing the RPC Protocol Binding Order

The default RPC protocol binding order is set when an Exchange Client is installed. This setting determines the protocol sequence that the client uses to communicate with Exchange Server. You can change the RPC binding order before or after the client is installed. You can improve performance by changing the RPC binding order if the client uses multiple protocols or if the single protocol your client uses is not the first listed in the RPC binding order. If the protocol that the Exchange Client uses is last in the sequence, the client attempts to bind over the protocols listed before that protocol when it connects to the server. The protocols are represented in the binding order, using the following entries. The string ncacn refers to Network Computing Architecture Connection. 
   Protocol name RPC protocol string
   ----------------------------------

   Local RPC      ncalrpc
   TCP/IP         ncacn_ip_tcp
   SPX            ncacn_spx
   Named pipes    ncacn_np
   NetBIOS        netbios
   VINES IP       ncacn_vns_spp
For example, the following entry attempts to establish connections over SPX, TCP/IP, and NetBIOS, in that order. 
   RPC_Binding_Order=ncacn_spx,ncacn_ip_tcp,netbios
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Clients Running Windows 95, Windows NT Server, and Windows NT Workstation

By default, the Exchange Client uses the following RPC binding order for Windows 95, Windows NT Server, and Windows NT Workstation when it connects to an Exchange Server computer.
  1. TCP/IP
  2. SPX
  3. Named pipes
  4. NetBIOS
  5. VINES IP (Windows NT Server and Windows NT Workstation only)
You can change the RPC binding order for clients running Windows 95, Windows NT Workstation, and Windows NT Server before or after you install the Exchange Client.

Before installation:
In Setup Editor, select the Binding Order property page.
After installation:

Use the Registry Editor to modify the binding order.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756  (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows


Locate and modify the following key in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Exchange Provider.
For example, the following entry establishes SPX, TCP/IP, and NetBIOS connections in the order indicated:
RPC_Binding_Order=ncacn_spx,ncacn_ip_tcp,netbios
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Clients Running Windows and Windows for Workgroups

By default, the Exchange Client uses the following RPC binding order for Windows for Workgroups when it connects to an Exchange Server computer.
  1. Named pipes
  2. SPX
  3. TCP/IP
  4. NetBIOS
  5. VINES IP
You can change the RPC binding order for clients running Windows and Windows for Workgroups before or after you install the Exchange Client.

Before installation:
In Setup Editor, select the Binding Order property page.
After installation:
In the Exchng.ini file in the Windows folder, edit the [Exchange Provider] section. For example, the following entry in the Exchng.ini file establishes SPX, TCP/IP, and NetBIOS connections in the order indicated: 
   [Exchange Provider]
   RPC_Binding_Order=ncacn_spx,ncacn_ip_tcp,netbios
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Clients Running MS-DOS

By default, the Exchange Client uses the following RPC binding order for MS-DOS when it connects to an Exchange Server computer.
  1. Local RPC
  2. Named pipes
  3. SPX
  4. TCP/IP
  5. NetBIOS
You can change the RPC binding order for clients running MS-DOS after you install MS-DOS. To change the order, edit the RPC_BINDING_ORDER line in the Mlsetup.ini file. This file is installed automatically on the client or on a network share. For example, the following entry in the Mlsetup.ini file establishes local RPC, named pipes, TCP/IP, and NetBIOS connections in the order indicated: 
   RPC_Binding_Order=ncalrpc,ncacn_np,ncacn_ip_tcp,netbios
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MORE INFORMATION

You do not need to restart the computer after you modify the Exchange binding order. The Exchange Client rereads the binding when it restarts. For troubleshooting purposes, simply change the binding order in the registry (make sure the key has been fully committed to the registry), and then perform a check names from the properties for the Exchange Server service (in Control Panel, double-click Mail). You do not even need to quit the Registry Editor when you try different bindings.

IMPORTANT: You MUST use commas between binding order entries, or the binding is not read. If, for example, you use "ncacn_ip_tcp;netbios" and perform a check names, the following error is immediately displayed:
The name could not be resolved. The Microsoft Address Book was unable to
log on to the Microsoft Exchange Server computer. Contact your system
administrator if the problem persists. <ok>
If you delete the entire RPC_binding_Order subkey, the Exchange Client uses the default binding order. This may be a good quick troubleshooting step if you have concerns about incorrect entries in the binding order.

The information in this article came from the Exchange Server Resource Kit on TechNet, and from other sources.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
136516  (http://support.microsoft.com/kb/136516/EN-US/ ) XCLN: Improving Windows Client Startup Times
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APPLIES TO
  • Microsoft Exchange Server 4.0 Standard Edition
  • Microsoft Exchange Server 5.0 Standard Edition
  • Microsoft Exchange Server 5.5 Standard Edition
  • Microsoft Exchange Client 5.5
  • Microsoft Exchange Client 5.0
  • Microsoft Exchange Client 4.0
  • Microsoft Outlook 97 Service Pack 1, when used with:
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
  • Microsoft Outlook 97 Standard Edition, when used with:
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
  • Microsoft Outlook 98 Standard Edition, when used with:
    • Microsoft Windows 98 Standard Edition
    • Microsoft Windows 95
    • Microsoft Windows NT 4.0
  • Microsoft Outlook, Exchange Server Edition
  • Microsoft Outlook 8.0 Exchange Server Edition for Macintosh
  • Microsoft Outlook 8.1 Exchange Server Edition for Macintosh
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Keywords: 
kbinfo kbsetup kbusage KB163576
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