If enabled, the default instance of the Microsoft SQL Server Database Engine listens on TCP port 1433. Named instances of the SQL Server Database Engine and SQL Server Mobile are configured for dynamic ports, which means they select an available port when the SQL Server service is started.
To assign a TCP/IP port number to the SQL Server Database Engine In SQL Server Configuration Manager, in the console pane, expand SQL Server 2005 Network Configuration, expand Protocols for , and then double-click TCP/IP. In the IPn Properties area box, in the TCP Port box, type the port number you wish this IP address to listen on, and then click OK.
In the console pane, click SQL Server 2005 Services. In the details pane, right-click SQL Server () and then click restart, to stop and restart SQL Server. After you have configured SQL Server to listen on a specific port there are three ways to connect to a specific port with a client application:
1. Run the SQL Server Browser service on the server to connect to the Database Engine instance by name.
2. Create an alias on the client, specifying the port number.
3. Program the client to connect using a custom connection string.