What are suitable protocols for securing VPN connections?

A.
S/MIME and SSH

B.
TLS and SSL

C.
IPsec and L2TP

D.
PKCS# and X.509

Explanation:
Both of them can be used to create and secure VPN’s. The Layer 2 Tunnel Protocol
(L2TP) is an emerging Internet Engineering Task Force (IETF) standard that combines the best
features of two existing tunneling protocols: Cisco’s Layer 2 Forwarding (L2F) and Microsoft’s
Point-to-Point Tunneling Protocol (PPTP). L2TP is an extension to the Point-to-Point Protocol
(PPP), which is an important component for VPNs. VPNs allow users and telecommuters to
connect to their corporate intranets or extranets. IPSec is a series of guidelines for the protection
of Internet Protocol (IP) communications. It specifies ways for securing private information
transmitted over public networks. Services supported by IPSec include confidentiality (encryption),
authenticity (proof of sender), integrity (detection of data tampering) and replay protection
(defense against unauthorized re-sending of data). It work on layer 3 of the OSI model and is the
most common protocols used to create VPNs.