Port 1433: MSSQL
Port 1433 is the default listener for Microsoft SQL Server. Like all database ports, it should be reachable only from application servers, never from the open internet.
TCPDatabasesUnencrypted by defaultIANA assigned
| Port number | 1433 |
|---|---|
| Service | Microsoft SQL Server |
| Protocol | TCP |
| Category | Databases |
| Default encryption | No |
Security note. Port 1433 is not encrypted by default. Restrict it to trusted networks, or use an encrypted alternative where one exists, to avoid exposing credentials and data in transit.
Frequently asked questions
What is port 1433 used for?
Port 1433 is the default listener for Microsoft SQL Server. Like all database ports, it should be reachable only from application servers, never from the open internet.
Is port 1433 TCP or UDP?
Port 1433 (MSSQL) uses TCP.
Is port 1433 secure?
Port 1433 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 1433 on my firewall?
Only if you specifically need MSSQL. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.