9.1. VPN Basics

A virtual private network session is an authenticated and encrypted communication channel across some form of public network, such as the Internet. Since the network is considered insecure, encryption and authentication are used to protect the data while it is in transit. Typically, a VPN is service independent, meaning that all information exchanged between the two hosts (Web, FTP [File Transfer Protocol], SMTP [Simple Mail Transfer Protocol], and so on) is transmitted along this encrypted channel.

Figure 9.1 shows a typical example of a VPN configuration. Two different networks are connected to the Internet. These two networks want to exchange information, but they want to do so in a secure manner, because some of the data ...

Get Mastering™ Network Security, Second Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.