Which port is designated for FTPS control traffic?

Which port is designated for FTPS control traffic?

• A. 21
• B. 989
• C. 990
• D. 53

Answer: (C)

FTPS can operate in two modes, and the port used for the control channel depends on which mode you’re using. In implicit FTPS, TLS begins immediately on the control connection, and this control channel is designated to run on a separate secure port. That port is the one reserved specifically for the FTPS control channel, which is why it’s the correct choice here. The other ports cover related but different functions: one is the standard FTP control port used when TLS isn’t implied or is upgraded later, another is the data channel port used for encrypted data transfer, and the last is used for DNS and is not part of FTP/FTPS control.

FTPS can operate in two modes, and the port used for the control channel depends on which mode you’re using. In implicit FTPS, TLS begins immediately on the control connection, and this control channel is designated to run on a separate secure port. That port is the one reserved specifically for the FTPS control channel, which is why it’s the correct choice here. The other ports cover related but different functions: one is the standard FTP control port used when TLS isn’t implied or is upgraded later, another is the data channel port used for encrypted data transfer, and the last is used for DNS and is not part of FTP/FTPS control.