Virtual Private Network

by Charles Scott, Paul Wolfe & Mike Erwin. O'Reilly & Associates, Inc. 1998. 177 pages. Index. Two Appendices. $29.95. ISBN 1-56592-319-7

Reviewed by Robert Bruen

Virtual Private Networks (VPN) have been around for a fairly short time still not widely deployed. They offer organizations a secure method for members to connect from any point on the internet to the home base but have it appear they are all on the local net. It is unlike connecting to your ISP then connecting to a home base machine where you are a peer at the ISP. With a VPN you still connect through your ISP (or whatever) but you are a peer on what appears to be you local net. This approach obviously has many advantages, especially in security, for people who travel and must have access to home base information and other resources.

As with most useful ideas there are difficulties in implementation that must be overcome first. For starters, the ISP you use needs to accommodate you by setting things up, which may or may not be a problem depending on the ISP. Someone who travels nationally may find a wide range of experiences when it comes to ease of use to various ISPs. Probably the biggest headache will be at the home base where the VPN will need to be administered, not unlike the usual experience we all have where management thinks that this is a good idea, but the resources will not be provided. The current staff will just add it on in spite of the fact it does require expertise and time to install and maintain.

This book goes through the steps necessary to get a VPN up and running with examples that come from having actually done it. It is intended to be a practical book, which may explain why it is a short book, and perhaps why it is an NT-centric book. There a couple chapters on what a VPN is, why you want one and a cost model (something technofolks often ignore).

Three products are explained: Point-to-Point Tunneling Protocol (PPTP), AltaVista Tunnel and the Cisco PIX Firewall, although these are not the only products in the marketplace. PPTP is an obvious choice because it is available with NT. There are a total of ten chapters with lots of diagrams including one on managing and maintaining a VPN.

I think the price is a little higher than it should be and I am still looking for a comprehensive book on VPN, but if you want a light introduction to VPN this is a helpful book. It is a quick read, especially if you know something about networks and security. There is more information available on the net including an IETF draft and some good articles from the press and vendors pages like Cisco.