CompTIA Network+ (N10-009)Network OperationsEasy
A network administrator needs to remotely manage a Linux server's command-line interface over an encrypted connection. Which default port should be allowed through the firewall?
- A22
- B23
- C3389
- D443
Show answer & explanationAnswer & explanation
Correct answer: A. 22
SSH (Secure Shell) uses TCP port 22 by default to provide encrypted remote command-line access, replacing the unencrypted Telnet protocol on port 23.
Why the other options are wrong
- B. Port 23 is used by Telnet, which is unencrypted.
- C. Port 3389 is used by RDP for Windows graphical remote desktop access.
- D. Port 443 is used for HTTPS web traffic, not CLI access.
SSH Port 22
SSH provides encrypted terminal/command-line access to remote devices and servers, using TCP port 22 by default.
- Replaces insecure Telnet (port 23)
- Uses TCP port 22
- Common for managing Linux servers, routers, and switches
Memory trick: SSH = Secure Shell, port 22, the safe twin of Telnet's 23.