SQL port numbers are an important consideration when configuring database connections. The default SQL port number is 1433 for Microsoft SQL Server. Knowing the common SQL port numbers and how to change them is useful for database administrators and developers.
The SQL port number indicates which port on a server will accept SQL connections. When a client wants to connect to a SQL database, it targets the server name and SQL port number to establish the connection. Without the proper port open, the client cannot communicate with the database.
SQL port 1433 is the default port used by Microsoft SQL Server. If installing SQL Server with the default settings, it will listen on TCP port 1433 for incoming queries and connections. As this is well known, port 1433 is frequently targeted by attackers attempting SQL injection or other attacks. For increased security, many administrators change the SQL port number.
Changing the SQL port number is done by modifying the TCP/IP settings within SQL Server Configuration Manager. This allows the port number to be altered from the default 1433 to another port such as 1500 or 1501. After changing the port, a restart of the SQL Server service is required for the new port number to take effect.
It’s important to communicate SQL port number changes with applications and users that need to connect to the database. Hardcoded connections will fail if the port is changed to a non-standard number. Setting the SQL port number to a very high number may also cause issues, as ports above 1023 may be blocked by firewalls.
In addition to the primary SQL port, there are several other common ports used for SQL Server connections. The SQL Server Browser service listens on UDP port 1434. Named pipe connections use TCP port 139. Mirroring uses TCP port 5022. Service Broker uses TCP port 4022. SQL Server Management Studio uses ports 135 and 445.
Knowing the common SQL port numbers allows proper configuration of firewalls. Only the necessary ports need to be opened to allow essential database connectivity. Unneeded ports can be closed to restrict access.
When connecting remotely to a SQL Server, the SQL port number must be included along with the server name or IP address. For example, a remote connection string may specify “123.123.123.123,1500” to target server 123.123.123.123 on port 1500. The SQL port number ensures the connection reaches the proper database instance.
As a review, the key SQL port numbers are 1433 for default SQL connections, 1434 for the SQL Browser service, and 135 and 445 for Management Studio. Changing the SQL port number from 1433 to a custom port boosts security but requires the new port number to be specified in all connection strings. Overall, being aware of the common SQL port numbers is critical for successful database administration and connectivity.