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Which protocol below uses TCP port 443 at layer 4?

A. HTML
B. HTTPS
C. TFTP
D. Telnet
E. SMTP
F. None of the above

Answer: B

Explanation:

HTTPS is the secured version of the HTTP application, which normally uses 128 bit SSL
encryption to secure the information sent and received on a web page. An example is a
banking web site, or a trustworthy shopping web site that takes credit card information. It
is an application layer protocol which uses TCP port 443.

Incorrect Answers:

A. HTML is not a protocol.
C. TFTP uses UDP port 69.
D. Telnet uses TCP port 23.
E. SMTP uses TCP port 25.