This article describes how to configure an instance of the SQL Server Database Engine to listen on a specific fixed port by using the SQL Server Configuration Manager. If enabled, the default instance of the SQL Server Database Engine listens on TCP port 1433. Named instances of the Database Engine and SQL Server Compact are configured for dynamic ports. This means they select an available port when the SQL Server service is started. When you are connecting to a named instance through a firewall, configure the Database Engine to listen on a specific port, so that the appropriate port can be opened in the firewall.
Because port 1433 is the known standard for SQL Server, some organizations specify that the SQL Server port number should be changed to enhance security. This might be helpful in some environments. However, the TCP/IP architecture permits a port scanner to query for open ports, so changing the port number is not considered a robust security measure.
The Database Engine begins listening on a new port when restarted. However, the SQL Server Browser service monitors the registry and reports the new port number as soon as the configuration is changed, even though the Database Engine might not be using it. Restart the Database Engine to ensure consistency and avoid connection failures.
To assign a TCP/IP port number to the SQL Server Database Engine
1. In SQL Server Configuration Manager, in the console pane, expand SQL Server Network Configuration, expand Protocols for <instance name>, and then double-click TCP/IP.
2. In the TCP/IP Properties dialog box, on the IP Addresses tab, several IP addresses appear in the format IP1, IP2, up to IPAll. One of these is for the IP address of the loopback adapter, 127.0.0.1. Additional IP addresses appear for each IP Address on the computer. (You will probably see both IP version 4 and IP version 6 addresses.) Right-click each address, and then click Properties to identify the IP address that you want to configure.
3. If the TCP Dynamic Ports dialog box contains 0, indicating the Database Engine is listening on dynamic ports, delete the 0.
4. In the IP Properties area box, in the TCP Port box, type the port number you want this IP address to listen on, and then click OK.
5. In the console pane, click SQL Server Services.
6. In the details pane, right-click SQL Server (<instance name>) 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:
- Run the SQL Server Browser service on the server to connect to the Database Engine instance by name.
- Create an alias on the client, specifying the port number.
- Program the client to connect using a custom connection string.