What does TCP port 20 primarily handle?

TCP port 20 is primarily used for FTP Data transfers. When a client initiates a file transfer using the File Transfer Protocol (FTP), port 21 is used for the control commands, while port 20 is designated for the actual data transfer between the client and server. FTP utilizes two channels: one for control (sending commands and responses) and the other for the transfer of file data.

This setup allows for efficient management of file transfer sessions. When a file is being sent from server to client, the transfer occurs over port 20, effectively separating the control communication from the actual data being transmitted. This is crucial for maintaining the integrity of the session and improving performance.