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Network protocols and network libraries

Applies to: SQL Server - Windows only

A server can listen on, or monitor, multiple network protocols at one time. However, each protocol must be configured. If a particular protocol isn't configured, the server can't 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 can't use dynamic port addresses (for example, when SQL Server connections must pass through a firewall server configured to pass through specific port addresses). Select an unassigned port number. Port number assignments are managed by the Internet Assigned Numbers Authority and are listed at https://www.iana.org.

To enhance security, network connectivity isn't 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.

Server message block protocol

Servers in the perimeter network should have all unnecessary protocols disabled, including Server Message Block (SMB). Web servers and Domain Name System (DNS) servers don't require SMB. This protocol should be disabled to counter the threat of user enumeration.

Effects of disabling SMB

Disabling SMB blocks the SQL Server or Windows Cluster service from accessing the remote file share. Don't disable SMB if you do or plan to do one of the following:

  • Use Windows Cluster Node and File Share Majority Quorum mode
  • Specify an SMB file share as the data directory during SQL Server installation
  • Create a database file on an SMB file share

Disable SMB

  1. On the Start menu, point to Settings, and then select Network and Dial-up Connections.

    Right-click the Internet-facing connection, and then select Properties.

  2. Select the Client for Microsoft Networks check box, and then select Uninstall.

  3. Follow the uninstall steps.

  4. Select File and Printer Sharing for Microsoft Networks, and then select Uninstall.

  5. Follow the uninstall steps.

Disable SMB on servers accessible from the internet

  • In the Local Area Connection properties, use the Transmission Control Protocol/Internet Protocol (TCP/IP) properties dialog box to remove File and Printer Sharing for Microsoft Networks and Client for Microsoft Networks.

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, and 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

For more information about endpoints, see Configure the Database Engine to listen on multiple TCP ports and Endpoints Catalog Views.

For more information about SQL Server network configurations, see Server network configuration.

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