Which TCP port is commonly used for FTP command and control communications?

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Multiple Choice

Which TCP port is commonly used for FTP command and control communications?

FTP keeps two separate channels: a control channel for commands and a data channel for the actual file transfers. The control channel is standardized to use TCP port 21, where login, directory commands, and session control are handled. The data channel is used for transferring files and, in active FTP, typically uses port 20 on the server side (while passive FTP uses a dynamic port range negotiated at runtime). That's why port 21 is the correct choice for command and control communications. The other ports belong to different services: 20 is tied to FTP data transfers in some modes, 22 is SSH, and 23 is Telnet.

FTP keeps two separate channels: a control channel for commands and a data channel for the actual file transfers. The control channel is standardized to use TCP port 21, where login, directory commands, and session control are handled. The data channel is used for transferring files and, in active FTP, typically uses port 20 on the server side (while passive FTP uses a dynamic port range negotiated at runtime). That's why port 21 is the correct choice for command and control communications. The other ports belong to different services: 20 is tied to FTP data transfers in some modes, 22 is SSH, and 23 is Telnet.

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