What exactly is a VPN?

What exactly is a VPN? There has been a lot of buzz around it, but why do we need it?

Over the past few months, there’s been a fair amount of hype surrounding Virtual Private Networks or VPN for short. The technology has even found its way into home routers and some of them even employ hardware-accelerated encryption. So, what is VPN and why do we need it at all? We’ll try our best to explain it without getting too geeky. 🙂

What is VPN?

Unfortunately, there’s no straightforward definition of VPN – not even in manuals. It’s crystal clear, they say: VPN stands for Virtual Private Network. Sleek, heh? It’s absolutely clear what ‘network’ is in this case.  ‘Private’ is also quite straightforward, meaning ‘not public’. In other words, such network selectively accepts only nodes with certain permissions.

First, everyone who accesses the private network and all the information they exchange needs to be tagged, so the users and data allowed into the private network could be distinguished from outsiders. Second, it is crucial to hide this information via encryption.

Third, there is a need to maintain the integrity of this private connection, meaning no outsiders should be allowed into the network, the messages should come only from the trusted sources, and the information should not leak anywhere in plaintext. Basically, it’s all about privacy – a good analogy is the parties of the rich and famous: everybody’s knows they happen but only a few know what happens behind those closed doors.

As for ‘Virtual’, that’s rather easy too. It means the network is abstracted from the physical substrate (the network thus does not care how many channels it employs, as it works transparently and integrally for all who have access). On the other hand, in most cases the virtual network does not belong to the owner of the physical network.
For example, any serious company would require any laptop or mobile device, which connects to any wired or wireless network, to access the corporate network exclusively over the VPN connection. It does not matter how this connection is established – in most cases, it will employ public connections which won’t even belong to the company. Such connection is called a ‘tunnel’ – and mind you, this term would be used multiple times later on.

Why do we need VPN?

The aforementioned example of a remote laptop connected to the corporate network is one of the most ubiquitous scenarios of using VPN in practice. The user feels at home (or, more accurately, feels at work while being at home, on vacations or in a business trip) and can conveniently access corporate data and services.

Moreover, in the security-consciuous enterprise sector, VPN is enabled by default on all devices used by employees. Even Internet access is deployed through the corporate network, which is usually heavily monitored by IT staff.

The second most ubiquitous scenario is similar to the one above, but in this case it’s not individual users who connect to a corporate network, but the entire branch offices or buildings. The goal is the same: to incorporate remote and distributed locations into a single, connected organisation.

Anyone can use a VPN to arrange a corporate network: from global enterprises to one-man band companies that are conscious of privacy and data protection.  The VPN can interconnect simple surveillance cameras, alarm systems and the like. With VPN being so simple (since there is no need to stretch a physical cable to all the locations), virtual private networks could function inside one organisation, just for the sake of separating certain departments and systems from one another.

VPNs are frequently used to connect servers and computing clusters to enable better availability and redundancy. The popularity of VPN is also related to the proliferation of cloud networking. Also: all the aforementioned solutions are not temporary: such VPNs are usually maintained over many years.

The opposite to a permanent VPN connection is what’s known as a session-based connection. They are frequently used to enable access to various services which process sensitive financial, healthcare and legal data.

But what good is a temporary connection?  Well, mobile phones and every day computers can make use of them.  In our tips for securing Android and iOS devices, we recommended to use a secure VPN connection to a trusted node (your home router of a VPN provider) when connecting to any public network, so your traffic is safe from potential interception prying eyes.

Finally, another reason to use VPS’s is to bypass physical limitations.  For instance, accessing web resources which are restricted on a particular territory.  Indeed, VPS’s for bypassing Netflix region lockouts is one of the more popular reasons people use them.  Also, according to a report by GlobalWebIndex, in 2014 alone, over 166 million people used VPN to access social networks.

Conclusion

It is obvious that VPN’s are useful for everyday folk, like you and me as well as huge corporations wanting to keep their secrets safe.  This is, of course, a very limited look at the VPN and if you’re still interested, there’s plenty of more technical literature out there on the internet that will give you a much more detailed look at this most useful of technologies.

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