Port 1433 — Microsoft SQL Server

Port 1433 — TCP

Connections to SQL Server instances using the standard TCP port.

What is port 1433 used for?

Connections between authorized applications and SQL Server.

Transport protocol

TCP

Security precautions

Do not expose the database directly to the Internet. Restrict access to authorized applications and servers.

Should we open this port in the firewall?

Allow this port only when a required service uses it. Apply least privilege: restrict authorized sources, destinations and interfaces, and log connections where appropriate.

How do I check this port?

Test-NetConnection SERVER -Port 1433

On Linux, nc -vz SERVER 1433 checks TCP connectivity only. A successful TCP connection does not validate the application, authentication or TLS configuration.

Port-to-service mappings are common conventions. Applications can use a different configured port; confirm the actual service and transport.