Port 1433 (MSSQL) — What It Is and How to Use It

Port 1433 is the default TCP port used by Microsoft SQL Server (MSSQL) for client-server communication. It is crucial for applications and users to connect to and interact with SQL Server databases, enabling data retrieval, manipulation, and administration.

Last updated: 2026-06-11

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                Port Number
                1433
            

Protocol MSSQL

Common Use Cases

Client applications connecting to a SQL Server database (e.g., business intelligence tools, custom applications)
Database administrators managing SQL Server instances remotely
Web servers or application servers connecting to a backend SQL Server database

Interactive Command Builder

Target Host / IP

Operating System

Generated Command

nc -zv example.com 1433

Check if Port 1433 is Open

sudo netstat -tuln | grep 1433

netstat -ano | findstr :1433

⚠️ Security Note: Leaving port 1433 open to the internet without proper security measures is a significant risk, as it exposes your SQL Server to potential attacks. Strong authentication, network firewalls, and encryption are essential.

Related Ports

Frequently Asked Questions

Is port 1433 dangerous to leave open?

Yes, leaving port 1433 open to the internet without strict firewall rules, strong authentication, and encryption is highly dangerous. It makes your SQL Server vulnerable to brute-force attacks, SQL injection, and other exploits.

What service uses port 1433?

Port 1433 is primarily used by Microsoft SQL Server (MSSQL) for its default instance to listen for incoming client connections.