When you have a lot of remote users -- and who doesn't these days -- you
need some way to connect them to the home office. But at the same
time, you need to make sure that they are connected securely. That
means, no one can see what the user is doing and, similarly,
outsiders can't piggyback onto your remote users' connections into
the home office and wreak havoc.
A virtual private network (VPN) is one solution. These software constructs surround your network connections to your remote folks with layers of encoding,
controlled by various protocols, that make it tough (nothing is
impossible) to break into the channel. This way the legitimate users
can connect to your home office and get the data they need, while
outsiders are kept... outside.
VPNs increase overhead, so operation will be slowed down quite a bit.
For example, I interrupted writing this tip to test the connection
speeds here at my remote office with three computers. All the
computers are connected through a cable router to a local cable ISP.
One is a Sony Vaio PCGF520, with 200M bytes of RAM and a 500-MHz
processor. It's connected to our corporate VPN. One is a Dell
Dimension with a 750 MHz Pentium III processor and 256M bytes of RAM,
not connected to the VPN, and the third is a slow old dog, a Gateway
P5-90, upgraded to 200 MHz, with 40M bytes of RAM. The last one can
barely get out of its own way, and I use it more as a print server
and modem server than anything else.
I went to
and conducted that site's
Internet download test, downloading 500K bytes into each computer.
The old dog came in with a speed of 866K bit/sec.; not great, but not
awful (the connection has a theoretical max speed of 10M bit/sec. The
Dell speedster delivered some impressive performance, clocking in at
1619K bit/sec.; only about 16% of the theoretical max, but still
double the speed of the old dog. Neither of these is connected to our
corporate VPN. But the Vaio, which isn't any slouch, and is connected
to our VPN, dawdled along at only 625K bit/sec.; 241K bit/sec. slower
than my resource-starved old dog. That test isn't definitive, of
course, but it gives an idea of the performance hit your users may
take with a VPN.
Moreover, some VPNs are a bit cranky. Frequently we'll see a message
from some erstwhile remote user of our VPN that he's unable to stay
on it. Personal experience indicates, however, that the good days FAR
outnumber the bad, and it's clear that the security advantages hugely
outweigh the performance disadvantages of using a corporate VPN for
Microsoft has a new link on its home page that takes you to a page
headed Professor Windows
deploying VPNs. This page will probably give you more than enough
information to get you started in deploying your own VPN. If you want
to give setup a try, follow the procedure below, which is on a link
from the Professor Windows page. (One note of caution -- this page
will probably change content periodically, so if you go to it in a
month or so it may not discuss VPNs any more.)
"To configure a VPN server, your computer must have at least two
interfaces. To setup a Windows 2000 server for VPNs, use the
1. Open Routing and Remote Access console in the Administrative Tools
2. Right-click the server and then click Configure and Enable Routing
and Remote Access.
3. The Routing and Remote Access Server Setup wizard starts; click
4. Select Virtual private network [VPN] server, and click Next.
5. Select or add a remote client protocol and click Next.
6. Specify the Internet connection for the server and click Next.
7. Choose a method to assign IP addresses to the clients, either
automatically or from a specified range of addresses, and click Next.
8. The next screen gives you an option to either configure this
server to use a RADIUS server or skip this step for now.
9. Click Finish to complete the Routing and Remote Access Server
Using a VPN isn't a simple matter, but you can start to test and make
sure you have the bugs out of your installation. Then follow with
deployment as the installation proves its worth.
This was first published in May 2001