CompTIA Network+ (N10-008) — Question 82

A network technician needs to ensure outside users are unable to telnet into any of the servers at the datacenter. Which of the following ports should be blocked when checking firewall configuration?

Answer options

• A. 22
• B. 23
• C. 80
• D. 3389
• E. 8080

Correct answer: B

Explanation

The correct answer is B, as port 23 is used by the Telnet protocol, which allows remote command-line access. Blocking this port will prevent telnet access from outside users. The other options represent different services: port 22 is for SSH, port 80 is for HTTP, port 3389 is for RDP, and port 8080 is often used for alternative web services, none of which relate to telnet.