Examkin

Question

Difficulty: MediumNetworking Ports and Protocols

A network administrator is establishing a new perimeter security policy for remote administration. The policy requires all administrative command-line connections and system file uploads to remote Linux servers to be encrypted using a single protocol suite. Which of the following default port numbers must be permitted through the firewall to satisfy this requirement?

  1. 22Answer
  2. B
    23
  3. C
    21
  4. D
    53

Answer

Port 22 should be allowed through the firewall to permit encrypted SSH and SFTP access.
TCP Port 22 is used by Secure Shell (SSH) and SSH File Transfer Protocol (SFTP). SSH provides an encrypted terminal connection for remote command-line administration, while SFTP leverages the same encrypted SSH channel to transfer files securely.

Step-by-Step Solution

1
Identify the functional requirements from the scenario.
The requirement calls for encrypted remote command-line administration and secure file transfers over a single protocol.
Security policy mandates encryption for administrative terminal sessions and file operations.
2
Map the required services to their corresponding standard TCP/IP protocols.
SSH (Secure Shell) provides encrypted remote terminal management, and SFTP operates over SSH to handle secure file transfer capabilities.
Both SSH and SFTP operate by default over TCP port 22.
3
Evaluate the option choices to select the matching default TCP port number.
Port 22 satisfies both requirements securely.
Ports 21 and 23 utilize unencrypted protocols (FTP and Telnet), while port 53 serves DNS name resolution.

Key Concept

Standard TCP/UDP Port Numbers and Secure Network Protocols
Rate this question

Topics

Networking Ports and Protocols

More questions from this topic