Which protocol is commonly used to securely access and administer network devices via a command-line interface on port 22?

Which protocol is commonly used to securely access and administer network devices via a command-line interface on port 22?

• A. Virtual Private Network (VPN)
• B. Secure Copy (SCP)
• C. Simple Mail Transfer Protocol (SMTP)
• D. Secure Shell (SSH)

Answer: (D)

Accessing a device’s command-line interface securely relies on an encrypted channel that protects both credentials and commands. Secure Shell enables remote login and interactive command execution over a secure channel, and port 22 is its default listening port. This combination is what makes SSH the standard method for securely administering network devices like routers and switches from the CLI. The other options don’t provide an interactive CLI session over port 22. A VPN creates a private tunnel for broader network access but isn’t itself a remote shell for device administration. Secure Copy uses SSH to transfer files but isn’t designed for interactive command execution. SMTP is for email and has no role in remote device management. So SSH is the protocol that fits the need of securely accessing and administering network devices via a command-line interface on port 22.

Accessing a device’s command-line interface securely relies on an encrypted channel that protects both credentials and commands. Secure Shell enables remote login and interactive command execution over a secure channel, and port 22 is its default listening port. This combination is what makes SSH the standard method for securely administering network devices like routers and switches from the CLI.

The other options don’t provide an interactive CLI session over port 22. A VPN creates a private tunnel for broader network access but isn’t itself a remote shell for device administration. Secure Copy uses SSH to transfer files but isn’t designed for interactive command execution. SMTP is for email and has no role in remote device management.

So SSH is the protocol that fits the need of securely accessing and administering network devices via a command-line interface on port 22.