ISC2 CISSP Certified Information Systems Security Professional Official Study Guide

by Mike Chapple

TCP/IP can be secured using virtual private network (VPN) links between systems. VPN links are encrypted to add privacy, confidentiality, and authentication and to maintain data integrity. Protocols used to establish VPNs are Point-to-Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP), Secure Shell (SSH), OpenVPN (SSL/TLS VPNs), and Internet Protocol Security (IPSec). Another method to provide protocol-level security is to employ TCP wrappers. A TCP wrapper is an application that can serve as a basic firewall by restricting access to ports and resources based on user IDs or system IDs. Using TCP wrappers is a form of port-based access control.