Which of the following protocols are used to secure a VPN connection?
Each correct answer represents a complete solution. Choose all that apply.

A.
IPSec

B.
TLS

C.
SSL

D.
L2TP

Explanation:
Internet Protocol Security (IPSec) is a standard-based protocol that provides the highest level of VPN security. IPSec can encrypt virtually everything above the networking layer. It is used for VPN connections that use the L2TP protocol. It secures both data and password. IPSec cannot be used with Point-to-Point Tunneling Protocol (PPTP). Layer 2 Tunneling Protocol (L2TP) is a more secure version of Point-to-Point Tunneling Protocol (PPTP). It provides tunneling, address assignment, and authentication. L2TP allows transfer of Point-to-Point Protocol (PPP) traffic between different networks. L2TP combines with IPSec to provide both tunneling and security for Internet Protocol (IP), Internetwork Packet Exchange (IPX), and other protocol packets across IP networks.

Answer B is incorrect. Transport Layer Security (TLS) is a cryptographic protocol that provides security and data integrity for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the Transport Layer endto- end. Several versions of the protocols are in wide-spread use in applications like web browsing, electronic mail, Internet faxing, instant messaging, and voice-over-IP (VoIP). The TLS protocol, an application layer protocol, allows client/server applications to communicate across a network in a way designed to prevent eavesdropping, tampering, and message forgery. TLS provides endpoint authentication and communications confidentiality over the Internet using cryptography.

Answer C is incorrect. The Secure Sockets Layer (SSL) is a commonly-used protocol for managing the security of a message transmission on the Internet. SSL has recently been succeeded by Transport Layer Security (TLS), which is based on SSL. SSL uses a program layer located between the Internet’s Hypertext Transfer Protocol (HTTP) and Transport Control Protocol (TCP) layers. SSL is included as part of both the Microsoft and Netscape browsers and most Web server products. URLs that require an SSL connection start with https. instead of http..