Which TCP port is utilized for FTP data transfer?

FTP (File Transfer Protocol) operates using two main ports for its functions: port 21 and port 20. Port 21 is used for the control connection, where commands are sent from the client to the server. Meanwhile, port 20 is specifically designated for FTP data transfer.

During an active FTP session, once the control connection is established through port 21, the actual data transfer uses port 20. This is essential for the FTP protocol to function correctly, as it separates the control information from the data being transferred.

Understanding this division between control and data ports is crucial for network design, firewall configuration, and security measures, as it helps in implementing methods to allow or block FTP traffic effectively.