Which of the following ports MUST be open on a firewall for TELNET to be used?

The correct answer is B. 23. Telnet uses TCP port 23 by default. Telnet is an older, unencrypted remote access protocol (largely replaced by SSH on port 22). Port 21 is FTP (file transfer), port 53 is DNS (domain name resolution), and port 110 is POP3 (email retrieval). For a firewall to allow Telnet…

Networking

Question

Which of the following ports MUST be open on a firewall for TELNET to be used?

Options

A21
B23
C53
D110

How the community answered

(31 responses)

A
3% (1)
B
90% (28)
C
6% (2)

Explanation

Telnet uses TCP port 23 by default. Telnet is an older, unencrypted remote access protocol (largely replaced by SSH on port 22). Port 21 is FTP (file transfer), port 53 is DNS (domain name resolution), and port 110 is POP3 (email retrieval). For a firewall to allow Telnet sessions, port 23 must be open.

Topics

#Telnet#port 23#firewall ports#network protocols

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