Which of the following are default ports for the FTP service? Each correct answer represents a complete solution. Choose two.

The correct answer is B. 20 C. 21. FTP (File Transfer Protocol) uses two separate ports by design: port 21 is the control channel, used to establish the connection and send commands, while port 20 is the data channel, used to actually transfer file contents. This dual-port design is a defining characteristic of…

Network Security Foundations

Question

Which of the following are default ports for the FTP service? Each correct answer represents a complete solution. Choose two.

Options

A443
B20
C21
D80

How the community answered

(42 responses)

A
7% (3)
B
81% (34)
D
12% (5)

Explanation

FTP (File Transfer Protocol) uses two separate ports by design: port 21 is the control channel, used to establish the connection and send commands, while port 20 is the data channel, used to actually transfer file contents. This dual-port design is a defining characteristic of FTP's active mode operation.

Port 443 (A) is HTTPS - encrypted web traffic over TLS/SSL. Port 80 (D) is standard HTTP - unencrypted web traffic. Both are web-related and have nothing to do with file transfer protocol.

Memory tip: Think "20 = data flows, 21 = commands fly" - the lower port carries the payload, the higher port carries the control conversation. Alternatively, remember 20-21 as sequential neighbors, both belonging to FTP, where 21 comes "first" to open the session before 20 does the actual work.

Topics

#FTP#Well-known ports#Network services#Port assignment

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