CompTIA Network+ (N10-006) — Question 24

A network administrator needs to allow employees to securely upload files to a remote server.
Which of the following should be allowed on the firewall?

Answer options

• A. 20
• B. 21
• C. 22
• D. 161

Correct answer: B

Explanation

Port 21 is used for FTP control commands, which is essential for file uploads. Port 20 is used for FTP data transfer, but for secure uploads, FTP over SSL/TLS (FTPS) is more suitable. Port 22 is typically used for SSH and secure file transfers with SFTP, while port 161 is used for SNMP, which is unrelated to file transfers.