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).
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
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.
- TCP/IP
- SPX
- Named pipes
- NetBIOS
- 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.
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may
require you to reinstall your operating system. Microsoft cannot guarantee that you can solve
problems that result from using Registry Editor incorrectly. Use Registry Editor at your own
risk.
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
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.
- Named pipes
- SPX
- TCP/IP
- NetBIOS
- 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
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.
- Local RPC
- Named pipes
- SPX
- TCP/IP
- 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