Port 1433 is the default for Microsoft SQL Server. On a Mac it usually means you're running SQL Server in Docker or a container for development. Run lsof -i :1433 to confirm.

Is it safe to kill the process on port 1433?

It stops your local SQL Server instance. That's safe for macOS, but stop the container or service gracefully rather than force-killing it so the database closes cleanly.

Should port 1433 be exposed to the internet?

No. SQL Server on 1433 is a frequent target for automated attacks. Keep it bound to localhost or your container network, never the public internet.

Port 1433: What's Using It and Is It Safe to Kill?

Port 1433 is the default port for Microsoft SQL Server. On a Mac, you’re most likely seeing it because you run SQL Server in a Docker container for development, since there’s no native macOS build.

What typically listens on port 1433

SQL Server in Docker: The standard way to run MS SQL on a Mac maps the container’s 1433 to the host.
Remote SQL Server connections: Connecting to a SQL Server on your network uses outbound 1433.
Database tooling: Some clients default to 1433 when connecting to Azure SQL or a local instance.

It sits in the registered range (1024-49151), so any process can bind it.

Is it safe to kill?

Stopping the listener won’t hurt macOS, but as with any database, shut it down cleanly rather than force-killing it mid-write. For a Docker instance:

docker stop <container>

That lets SQL Server flush and close properly. Only kill the PID directly if it’s genuinely stuck.

Is it suspicious?

On a machine where you do SQL Server development, no. It’s expected. Worth checking: that it’s bound to localhost or your container network rather than exposed. A 1433 listener reachable from outside your machine is a well-known attack target and should be locked down.

How to find what’s on port 1433 on macOS

lsof -i :1433

To stop a stuck process by PID:

kill $(lsof -ti :1433)

Portie shows port 1433 with its owning process in its live view, so you can confirm whether your SQL Server container is the one holding it.