Client Net-Libraries and Network Protocols
Microsoft® SQL Server™ uses a dynamic-link library (DLL) called a
By themselves, a pair of Net-Libraries cannot support a client/server connection. Both the client and server also must be running a protocol stack supporting the Net-Libraries. For example, if the server TCP/IP Sockets Net-Library is listening on the server computer, and the client TCP/IP Sockets Net-Library is configured to connect to that server on the client computer, the client can only connect to the server if a TCP/IP protocol stack is installed on both computers.
Multiple Network Protocol Support
The Named Pipes and Multiprotocol Net-Libraries both support multiple network protocols (NW Link IPX/SPX, NetBEUI, and TCP/IP), and will select automatically any supported network protocol that is available. Using either of these Net-Libraries is useful if the client must connect to multiple servers running different network protocols, and you do not want to create and manage configuration entries for each server-network protocol combination.
Net-Library Setup and Defaults
The client Net-Libraries are installed during SQL Server Setup. You define which client Net-Libraries are used to connect to particular instances of SQL Server using the Client Network Utility. You can specify a default Net-Library for all connections and also define the use of specific Net-Libraries for connecting to specific instances of SQL Server. TCP/IP is the default protocol on clients running the Microsoft Windows NT® 4.0, Windows® 2000, Windows 95, or Windows 98 operating system.
SQL Server can be listening simultaneously on any combination of server Net-Libraries. Use SQL Server Network Library Configuration during or after the Setup program to choose the server Net-Libraries to be activated.
For computers running Windows NT 4.0 or Windows 2000, the default server Net-Libraries are:
- TCP/IP Sockets.
- Named Pipes.
For computers running Windows 98, the default server Net-Libraries are:
- TCP/IP Sockets.
- Shared Memory.
When you install SQL Server client utilities on a workstation, SQL Server Setup installs TCP/IP as the default client protocol.
If most of the servers to which you will be connecting are not configured to support the current default client protocol, you can change the default to another protocol.
For more information about the SQL Server Net-Libraries and the network protocols they support, see Communication Components.
SQL Server 2000 can use the Secure Sockets Layer (SSL) to encrypt all data transmitted between an application computer and an instance of SQL Server on a database computer. Both the client and the server computers must have the proper certificates installed for SSL encryption to function.
Because the Shared Memory Net-Library is used only for intra-computer communications, it is inherently secure and does not need encryption. For more information, see Net-Library Encryption.