This chapter explores and defines some of the challenges and problems presently associated with using the Internet as a virtual private network or extranet. (The terms Internet as a virtual private network, virtual private network or VPN, and extranet are used as synonyms in this chapter and throughout this book.) Many of these problems are being solved as I write this and thus represent opportunities as well as challenges. The primary objective of this chapter is to describe and define these problems so that the solutions to them that are described later in this book can be clearly understood by the reader. At the end of this chapter, I'll comment on the use of demilitarized zones or DMZs, which solve many of the problems discussed here.

There are two kinds of illustrations used in this chapter. The boxes with text in them are brief summaries of the challenges and problems described in this chapter. The other illustrations are meant to be interesting and to suggest some of the issues and complexities discussed in this chapter in a more artistic and abstract way. An objective of this chapter is to offer the reader a little bit of fun and humor in addition to practical knowledge by using the art work in this chapter to entertain, amuse, and inform.

The problems or challenges described in this chapter include the: