Network Protocols and Network Libraries

A server can listen on, or monitor, multiple network protocols at one time. However, each protocol must be configured. If a particular protocol is not configured, the server cannot listen on that protocol. After installation, you can change the protocol configurations using the SQL Server Configuration Manager.

Default SQL Server Network Configuration

A default instance of SQL Server is configured for TCP/IP port 1433, and named pipe \\.\pipe\sql\query. SQL Server named instances are configured for TCP dynamic ports, with a port number assigned by the operating system.

If you cannot use dynamic port addresses (for example, when SQL Server connections must pass through a firewall server configured to pass through specific port addresses), we recommend using a port address number ranging from 49152 through 65535. Port number assignments are managed by the Internet Assigned Numbers Authority and are listed at

To enhance security, network connectivity is not fully enabled when SQL Server is installed. To enable, disable, and configure network protocols after Setup is complete, use the SQL Server Network Configuration area of the SQL Server Configuration Manager.

Types of Endpoints

SQL Server introduces a new concept for SQL Server connections; the connection is represented on the server end by a Transact-SQL endpoint. Permissions can be granted, revoked, and denied for Transact-SQL endpoints. By default, all users have permissions to access an endpoint unless the permissions are denied or revoked by a member of the sysadmin group or by the endpoint owner. The GRANT, REVOKE, and DENY ENDPOINT syntax uses an endpoint ID that the administrator must get from the endpoint's catalog view.

SQL Server Setup creates Transact-SQL endpoints for all supported network protocols, as well as for the dedicated administrator connection.

Transact-SQL endpoints created by SQL Server Setup are as follows:

  • Transact-SQL local machine

  • Transact-SQL named pipes

  • Transact-SQL default TCP

  • Transact-SQL  default VIA


    The VIA protocol is deprecated. This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

For more information about Transact-SQL endpoints, see "Network Protocols and TDS Endpoints" in SQL Server Books Online.

For more information about SQL Server network configurations, see the following topics in SQL Server Books Online:

  • "Server Network Configuration"

  • "Configuring Server Network Protocols and Net-Libraries"

  • "Default SQL Server Network Configuration"

  • "Net-Libraries and Network Protocols"