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

A.
PEAP

B.
L2TP

C.
IPSec

D.
PPTP

Explanation:
The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks. PPTP does not provide confidentiality or encryption. It relies on theprotocol being tunneled to provide privacy. It is used to provide secure, low-cost remote access to corporate networks through public networks such as the Internet. Using PPTP, remote users can use PPP- enabled client computers to dial a local ISP and connect securely to the corporate network through the Internet. PPTP has been made obsolete by Layer 2 Tunneling Protocol (L2TP) and IPSec. 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. 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).

Answer A is incorrect. PEAP (Protected Extensible Authentication Protocol) is a method to securely transmit authentication information over wired or wireless networks. It was jointly developed by Cisco Systems, Microsoft, and RSA Security. PEAP is not an encryption protocol; as with other EAP protocols, it only authenticates a client into a network. PEAP uses server-side public key certificates to authenticate the server. It creates an encrypted SSL/TLS (Secure sockets layer/Transport layer security) tunnel between the client and the authentication server. In most configurations, the keys for this encryption are transported using the server’s public key. The resultant exchange of authentication information inside the tunnel to authenticate the client is then encrypted and the user credentials are thus safe and secure.

Reference. http.//en.wikipediA.org/wiki/Virtual_private_network