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Question

Difficulty: MediumRemote Access Technologies and Tools

A network administrator needs to configure secure, remote command-line access to manage a Linux server over an untrusted public network. Which protocol and default port combination should be permitted through the network firewall?

  1. SSH on TCP port 22Answer
  2. B
    Telnet on TCP port 23
  3. C
    RDP on TCP port 3389
  4. D
    VNC on TCP port 5900

Answer

SSH on TCP port 22 is the correct choice because it provides an encrypted command-line session suitable for remote Linux administration.
SSH (Secure Shell) on TCP port 22 provides strong encryption for remote terminal sessions, securing credentials and command-line traffic transmitted across public networks.

Step-by-Step Solution

1
Identify access requirements
The scenario requires command-line (terminal) management over an untrusted network.
Administrative commands and login credentials must be protected against eavesdropping.
2
Evaluate protocol security and function
SSH encrypts session traffic by default and provides shell access, whereas Telnet sends plaintext traffic.
Unencrypted protocols like Telnet expose credentials to packet sniffing attacks.
3
Match protocol to standard default port
SSH uses TCP port 22.
Firewall rules must permit TCP port 22 to allow inbound SSH sessions.

Key Concept

Remote Access Protocols and Ports (SSH vs Telnet / RDP / VNC)
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Topics

Remote Access Technologies and Tools

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