Which service commonly runs on port 22?

Which service commonly runs on port 22?

• A. Secure Shell (SSH)
• B. FTP
• C. Telnet
• D. SMTP

Answer: (A)

Default port assignments link a service to a well-known port, helping devices know what to expect when connecting. The service that commonly runs on port 22 is Secure Shell, which provides encrypted remote login and command execution, along with secure file transfers like SFTP and SCP. Because SSH is designed for secure remote administration, port 22 is its standard default. FTP typically uses ports 20 and 21; Telnet uses port 23 and transmits data in plaintext; SMTP uses port 25 for mail transfer. Understanding these defaults helps you quickly identify the intended service when you see a given port in logs or firewall rules.

Default port assignments link a service to a well-known port, helping devices know what to expect when connecting. The service that commonly runs on port 22 is Secure Shell, which provides encrypted remote login and command execution, along with secure file transfers like SFTP and SCP. Because SSH is designed for secure remote administration, port 22 is its standard default. FTP typically uses ports 20 and 21; Telnet uses port 23 and transmits data in plaintext; SMTP uses port 25 for mail transfer. Understanding these defaults helps you quickly identify the intended service when you see a given port in logs or firewall rules.