FTP control commands are transmitted over which TCP port?

FTP (File Transfer Protocol) operates over two different channels: a command channel and a data channel. The control commands, which are used to establish the connection and manage the session, are specifically transmitted over TCP port 21. This is where the client sends commands to the server, such as login requests and file operations.

Port 20 is commonly used for the data transfer in active mode FTP sessions, but it is the control commands that uniquely identify port 21. Hence, understanding the separation of control and data channels is fundamental to comprehending the workings of FTP.

The other options, such as ports 22 and 23, are associated with different protocols—SSH (Secure Shell) and Telnet, respectively—while port 20 typically relates to the data transfer aspect of FTP itself. Therefore, port 21 is the designated port for FTP control commands.