14. Virtual Private Network uses
public lines to link PCs
By Mark Alberstat
I ran across an acronym in an e-mail the other day and would like to know
what it stands for. The letters are VPN.
VPN is an acronym people are hearing more and more recently but not a lot
of people understand what they are or if they are operating on one.
VPN, or Virtual Private Network, uses public lines to connect PCs to each
other and other networked elements. VPNs are much like WANs, or Wide Area
Networks, but the main difference is the use of public lines.
Because of this, encryption is a key to their use and efficiency. Saving
money by using public lines could quickly be undermined by competitors or
12-year-old hackers being able to retrieve your information as it goes
skipping around the Internet.
VPNs have become increasingly popular as more companies have employees
working far from their main offices or on the road. Hooking into a VPN
gives that staff member a secure link to his or her office system to check
supply, pick up mail, view documents or do any other task that could be
done if sitting in their office attached to the company's main LAN, or
Local Area Network.
This is all done, of course, without the use of expensive leased lines or
even long-distance charges if the remote worker uses a local exchange to
get onto the Internet and then into their company's network.
VPNs can be built in several ways; the most popular and flexible one being
based on IP, or Internet Protocol. The popularity of this type stems from
the fact that most companies' internal networks are based on IP
technology, as well as making the connection to and use of the internal
network relatively easy and familiar to most users.
When establishing a VPN the company's IT group has to decide what type of
architecture they will use. There are three choices: hardware-based
systems, firewall-based systems and software-based systems.
The hardware systems were the first to find their way onto the marketplace
and are a type of encrypted router, something most network administrators
are familiar with. Firewall-based VPNs are the most secure type and rely
on the firewall's existing security.
The most flexible type is the software-based VPN. These are more popular
when both ends of the VPN are not owned by the same company, such as a
customer dialing in to check on inventory.
A few of the companies creating VPN hardware include Cisco, 3Com, Nortel
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Originally published 3 August 2003