What’s a VPN?

There is no doubt that the term VPN causes much confusion throughout the IT industry never mind the public.  This is due to a number of reasons, but the confusion is largely to do with evolving technologies and how VPNs adapt with them.  The traditional definition of a VPN (Virtual Private Network) is as follows;

A private network for voice and data built with carrier services.

It’s a definition that was perfectly adequate for many years however, more recently, a VPN has come to describe the establishing of private and encrypted tunnels through the internet for transporting voice and data. So here’s some more up to date and hopefully more accurate definitions as described by the LAN Times Encyclopedia of Networking –

• Voice VPN – a single carrier handles all your voice call switching. The ‘virtual’ in VPN implies that the carrier creates a virtual voice-switching network for use by utilising it’s own switching equipment.
• Carrier-based voice data VPN – Packet, frame and cell switching networks carry information in discrete bundles (packets) that are routed through a mesh of network switches to their destination. Carriers can program virtual circuits into these networks that simulate dedicated connections between perhaps specific sites or locations (within a company’s control). A web of these virtual circuits can form a virtual private network over a controlled packed switched network.

Virtual Private Networks for your PC

The new guy on the block and the most likely technology if you see it mentioned on the internet outside the IT department is this –

• Internet VPN – an internet VPN is similar to the previous two definitions except that the IP-based internet is the underlying network.

So in definition an Internet VPN is simply a secure way to move packets across the internet using specialised equipment. It can be done using a variety of methods using a Transport mode, encrypting just the payload and leaving the headers readable so the packet can be forwarded by any hardware across the internet. The other method is Tunnel mode, which can be used with protocols like IP, IPX and SNA to encrypt and encapsulate into new IP packets for distribution, this technique is more secure as it also hides both the source and destination of the packet as well.

A Tunnel mode Internet VPN, is probably the most likely technology that is being discussed when you see and hear discussion of a VPN online. Here’s a practical example of one of the commercially popular VPN technologies available on the internet, for an individual who doesn’t want to invest in the extensive infrastructure required – this is an example of how you can buy VPN online.

Here you can see a low cost, highly secure internet VPN which can be used to provide security, hide all your online activities and obscure your exact location from any web site you visit.  It’s in my opinion the best UK VPN you can buy without moving into the high cost business market.  This particularly has become much more important over the years with the rise of geolocation, where web sites block access based on your location. Using a VPN tunnel you can change your virtual location at will, which millions now use as useful tool to watch websites that are normally inaccessible to them.