Which of the following is a client-server program that opens a secure, encrypted command-line shell session from the Internet for remote logon?

Which of the following is a client-server program that opens a secure, encrypted command-line shell session from the Internet for remote logon?
A . VPN
B . IPsec
C . SSH
D . SFTP

Answer: C

Explanation:

The correct answer is C. SSH.

SSH stands for Secure Shell, a client-server program that opens a secure, encrypted command-line shell session from the Internet for remote logon. SSH allows users to remotely access and execute commands on a server without exposing their credentials or data to eavesdropping, tampering or replay attacks. SSH also supports secure file transfer protocols such as SFTP and SCP1.

VPN stands for Virtual Private Network, a technology that creates a secure, encrypted tunnel between two or more devices over a public network such as the Internet. VPN allows users to access resources on a remote network as if they were physically connected to it, while protecting their privacy and identity2.

IPsec stands for Internet Protocol Security, a set of protocols that provides security at the network layer of the Internet. IPsec supports two modes: transport mode and tunnel mode. Transport mode encrypts only the payload of each packet, while tunnel mode encrypts the entire packet, including the header. IPsec can be used to secure VPN connections, as well as other applications that require data confidentiality, integrity and authentication3.

SFTP stands for Secure File Transfer Protocol, a protocol that uses SSH to securely transfer files between a client and a server over a network. SFTP provides encryption, authentication and compression features to ensure the security and reliability of file transfers.

1: SSH (Secure Shell) 2: What is a VPN? How It Works, Types of VPN | Kaspersky 3: IPsec – Wikipedia: [SFTP – Wikipedia]