Setting the Default Net-Library

When you install SQL Server client utilities on a workstation you can specify the client's default Net-Library, which supports communication between the client and SQL Server. (The setup program's default is to set the Named Pipes Net-Library as the default.) However, if after installation you determine that the client will be regularly connecting to a server that is not configured to support the client's default interprocess communication (IPC) mechanism (for example, NWLink IPX/SPX), after installation you can change the client's default Net-Library.

For Windows NT-, Windows 95-, and Windows-based clients, change the default Net-Library by using the SQL Client Configuration Utility.
For MS-DOS - based clients, change the default Net-Library by loading a different Net-Library TSR program.

The following table lists the SQL Server client Net-Libraries for the Windows NT, Windows 95, Windows, and MS-DOS operating systems:



Net-Library	Windows NT or Windows 95	Windows (1)	MS-DOS

Named Pipes	DBNMPNTW.DLL	DBNMP3.DLL	DBNMPIPE.EXE
NWLink IPX/SPX	DBMSSPXN.DLL	DBMSSPX3.DLL	DBMSSPX.EXE
Banyan VINES	DBMSVINN.DLL	DBMSVIN3.DLL	DBMSVINE.EXE
TCP/IP Sockets	DBMSSOCN.DLL	DBMSSOC3.DLL	Not available
Multi-Protocol	DBMSRPCN.DLL	DBMSRPC3.DLL (2)	Not available
(1) 16-bit Windows: Microsoft Windows 3.11 and Microsoft Windows for Workgroups. (2) The Multi-Protocol Net-Library used by Windows-based clients (DBMSRPC3.DLL) also uses the following runtime DLLs: RPCNS1.DLL, RPCRT1.DLL, RPC16C3.DLL, RPC16C1.DLL, RPC16DG3.DLL, RPC16C4.DLL, RPC16C5.DLL, RPC16C6.DLL, RPC16DG6.DLL and SECURITY.DLL. These are provided with SQL Server and installed by the setup program as Net-Libraries.

Connection limits for each of these Net-Libraries are shown in the following table:



Net-Library	Windows NT or Windows 95	Windows	MS-DOS

Named Pipes	No limit (1)	34 (2)	15 (3)
NWLink IPX/SPX	No limit (1)	25 (2,4)	15 (5)
Banyan VINES	No limit (1)	15	15
TCP/IP Sockets	No limit (1)	6	N/A
Multi-Protocol	No limit (1)	No limit (6)	N/A
(1) Limited only by operating-system memory resources. (2) Might vary with different versions of DB-Library and the Net-Library (due to possible differences in the sizes of some internal data structures). (3) Limited by the number of available MS-DOS file handles. (4) The Windows-based client Net-Libraries use one IPX socket per connection and one to three SPX sessions per connection. To achieve the maximum number of connections, set the IPX Sockets parameter to 32 and the SPX Connections parameter to 96 in the SHELL.CFG file. You may also need to change the Novell NET.CFG file. (5) The MS-DOS - based client Net-Libraries use one IPX socket per connection and one to three SPX sessions per connection. To achieve the maximum number of connections, set the IPX Sockets parameter to 22 and the SPX Connections parameter to 66 in the SHELL.CFG file. (6) Limit is determined by the underlying protocol that is being used.

To set the default Net-Library for Windows NT- or Windows 95-based clients

Start the SQL Client Configuration Utility as described in Starting the Client Configuration Utility, earlier in this chapter.
The SQL Client Configuration Utility window appears.
Choose the Net-Library tab.
From the list in the Default Network box, select a Net-Library.
Choose the Done button.

To set the default Net-Library for Windows-based clients

From the SQL Server Tools program group, double-click the SQL Client Configuration Utility icon.

The SQL Client Configuration Utility window appears.
From the list in the Default Network box, select a Net-Library.
Choose the Change button.
Choose the Done button.

To set the default Net-Library for MS-DOS - based clients

Using a text editor, edit the computer's AUTOEXEC.BAT file so that it loads the appropriate Net-Library TSR at system startup.

MS-DOS - based clients use terminate-and-stay-resident (TSR) programs to communicate with the underlying network layer. Only one Net-Library TSR can be loaded at a time. These TSR programs are included with the client software for MS-DOS - based clients: :

Named Pipes (DBNMPIPE.EXE)
Novell SPX (DBMSSPX.EXE)
Banyan VINES (DBMSVINE.EXE)

Note that MS-DOS-based clients do not support TCP/IP sockets and Multi-Protocol.

During installation, the setup program gives you the option of selecting one of the TSR programs for automatic loading every time the operating system starts, and of adding the \SQL\BIN directory to the system path. If you do not select this setup option, you will need to load the TSR manually. You may also need to make sure the \SQL\BIN directory is in the path.

A TSR can be manually loaded by typing its executable name from a command prompt (for example, type dbnmpipe).

Since only one TSR can loaded at once, a loaded TSR must be unloaded before a different TSR can be loaded. To stop a loaded TSR, run the ENDDBLIB.EXE utility (from a command prompt, type enddblib).

You can also set the default MS-DOS Net-Library by editing the AUTOEXEC.BAT file.