Several different tunneling protocols can be used in dial-up situations. Which of the following would be best to use as a VPN tunneling solution?

A.
L2P

B.
PPTP

C.
IPSec

D.
L2TP

Explanation:
B: A virtual private network (VPN) is a secure, private connection through a public network or an otherwise unsecure environment. It is a private connection because the
encryption and tunneling protocols are used to ensure the confidentiality and integrity of the data in transit. It is important to remember that VPN technology requires a tunnel to
work, and it assumes encryption. The protocols that can be used for VPNs are Point-to-Point Tunneling Protocol (PPTP), IPSec, and L2TP. Point-to-Point Tunneling Protocol
(PPTP), a Microsoft protocol, allows remote users to set up a PPP connection to a local ISP and then create a secure VPN to their destination. PPTP has been the de facto
industry-standard tunneling protocol for years, but the new de facto standard for VPNs is IPSec. PPTP is designed for client/server connectivity and establishes a single point-topoint
connection between two computers. It works at the data link layer and transmits only over IP networks.
A is incorrect because L2P does not exist. This is a distracter answer.
C is incorrect because although IPSec is one of the three primary VPN tunneling protocols, it is not used over dial-up connections. It supports only IP networks and works at
the network layer, providing security on top of IP. IPSec handles multiple connections at the same time, and provides secure authentication and encryption.
D is incorrect because L2TP is not a tunneling protocol that works over a dial-up connection. L2TP is a tunneling protocol that can extend a VPN over various WAN network
types (IP, X.25, frame relay). A hybrid of L2F and PPTP, L2TP works at the data link layer and transmits over multiple types of networks, not just IP. However, it must be
combined with IPSec for security so it is not considered a VPN solution by itself.