Which of the following protocols or technologies do you use each time you connect remotely through VPN?

(A) TLS
(B) IPsec
(C) SSH
(D) Telnet
(E) FTPS

TLS is the correct answer.

The term remote access VPN, or client VPN, typically refers to a VPN for which one endpoint is a user device, such as a phone, tablet, or PC. In those cases, Transport Layer Security (TLS) is the more likely protocol to use. TLS is included in browsers and is commonly used to connect securely to websites. Internet VPNs can provide important security features, such as the following:

• Confidentiality (privacy): Preventing anyone in the middle of the Internet (man in the middle) from being able to read the data.
• Authentication: Verifying that the sender of the VPN packet is a legitimate device and not a device used by an attacker.
• Data integrity: Verifying that the packet was not changed as the packet transited the Internet.
• Anti-replay: Preventing a man in the middle from copying and later replaying the packets sent by a legitimate user, for the purpose of appearing to be a legitimate user.

To accomplish these goals, two devices near the edge of the Internet create a VPN, called a VPN tunnel.