Port 6666 is used by Databricks for secure cluster connectivity, specifically when using PrivateLink.

What is PrivateLink?

PrivateLink lets you connect to Databricks resources (like your workspace) through your private network without exposing them to the public internet. This enhances the security of your Databricks environment.

Why Port 6666?

When you use PrivateLink, traffic between your network and Databricks is routed through a private endpoint. Port 6666 is used for this secure communication.

When do you need to open Port 6666?

You only need to open port 6666 in your firewall or security groups using PrivateLink to connect to Databricks.

Additional Information:

• Importance of Opening Ports: If you’re using PrivateLink and have yet to open port 6666, you won’t be able to connect to your Databricks workspace securely.
• Other Ports: Databricks uses other ports for different purposes (443, 3306, 8443-8451). By January 31, 2024, you must ensure these ports are also open for your Databricks deployment to function correctly.