From The Naked PC issue #5.07...

Virtual Private Networks

by T.J. Lee
March 28, 2002

The Internet has truly changed the landscape of computing. For me, the most profound change has been to provide a networking structure that spans the globe.

My first experience with the Internet was like most others, surfing the World Wide Web. While a terrific method to disseminate information, the Web is not really network-like at all. There's no concept of persistent connections so some amazing kludges have been developed over the years to make the Web appear to work like a network. But the Internet itself is very much a network and what's more, it can be used as such.

To illustrate what I'm talking about let's journey back to the olden days when most of the crew that cranks out The Naked PC used to work on a printed publication called Woody's Underground Office Newsletter, or WUON for short. One of Dan Butler's first articles in WUON was one called "Peering Across the Internet." I was one of the editors on WUON and I remember the first line of Dan's article, which caught my eye. It was "Imagine editing a document on a computer across the country or even the world for that matter." I was staggered... could the Internet really allow one to do this? As I learned from Dan's article it was very possible to do this. Dan's article was, and still is, a great article on this subject. I spoke with Dan late into the night after that first reading and we created one of the peer-to- peering across the Internet networks that he had written about. I was printing my local documents on Dan's color printer three states away. It was heady stuff for dial-up connections back in those days. You can read Dan's original article here:
http://www.TheNakedPC.com/t/507/tr.cgi?jim1

It was not a very secure network by any means but we had our machines networked as though we were on a traditional LAN. Only we were using the public Internet as the method of connectivity instead of coax or twisted pair wiring. The drawback was the lack of security. Enter virtual private networks (VPN) over the Internet.

VPNs solved the security problem by encrypting the packets sent out across the Internet from a computer at one end and decrypting them at the computer at the other end. I've recently had some first hand experience with VPNs where I work and the results are nothing less than amazing.

VPN allows a computer (which I'll call the remote computer) with Internet access to attach to a network using the Internet as though it were a very long patch cord. In other words, a VPN lets you work as though the remote computer were sitting in the office plugged into the network and not a jillion miles away and only plugged into the Internet.

A VPN is created by software, one piece running on the remote computer and talking to software running on the network at the other end. This type of connection is often referred to as a VPN tunnel. The software at the network end may be running as part of the network server operating system or it may be a third party product running in firmware such as that found on some CISCO firewalls (CISCO also provides a client component allowing remote computers to VPN into the firewall). Windows XP and Windows 2000 have VPN software "built-in" making the creation of virtual private networks fairly easy depending on how the server or host system is set up and how it's connected to the Internet.

When you've established a VPN connection it's as though you have plugged directly into the network you are establishing the tunnel with. However, there are different ways the tunnel can be established and this can influence what you have to do in order to interact with the network.

For example, if you log into your local computer before the tunnel is created you will have access to the network but won't have the benefit of the network login scripts that would normally be executed when you log into the network from a computer directly connected.

The solution is to create the tunnel before you log onto your remote computer. Establishing the tunnel before logging in lets you log into the network as though you were directly connected. The normal login scripts are run and you get your mapped drives, network printers etc. This saves you from having to do all this manually after creating the tunnel.

If your network uses roaming profiles you should see the same desktop you'd see at the office and anything you could do at the office you can now do from anywhere in the world where you can access the Internet with your remote computer except maybe get a cup of coffee from the office coffee pot.

Yes, I know, you are always limited when traversing the Internet by your Internet connection speed so it won't seem exactly like you were connected directly. Needless to say, this all works better with a high speed connection such as DSL or cable modem but work it does and is absolutely the berries for working remotely or telecommuting in to the office.

You can reach T.J. Lee at:
mailto:tj_lee@TheNakedPC.com
(John Heffron of McMillan Consulting contributed to this article.)

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