Networking always amaze me. Sometimes I feel like I should have been studied networking more. Anyways…back to the point. I will try to describe what actually "Virtual Private Network" is. Let’s take a real life example.
As companies business expands, company opens up more offices across the various countries and around world. Generally people working from remote locations are sales people. Sales people always need to travel across countries and need to work while they are travelling or from remote locations around the globe. In such case, people working remotely need a fast, secure and reliable way to share information across computer networks of the company.
The technology which helps you to achieve this is Virtual Private Network. VPN is network which uses either private network or public network means internet to share information from remote locations. The information passed over VPN is always encrypted hence anyone can’t read this encrypted data. While using VPN over internet we use connections routed through internet only; still it gives us feel like we are working in private network by enabling us to access the desired network resources. Hence the connection established in VPN is not establishing any actual physical private network. It works over public network only, however it gives feel of working in private network by securing the information and provides seamless connectivity to desired network resources, therefore VPN is referred as Virtual.
To understand VPN let’s consider an example of real life and following diagram –
As shown in the diagram, let’s say there are many islands in OCEAN and you live on island 3 present in OCEAN. To travel from island 3 to any other island we need to use Boat. Let’s say the boat is open from all the sides and has no roof or compartment. However, travelling with boat is not secured as anyone from other island can see what you are carrying in boat and what you are doing on boat. Hence no privacy [Please see route number 1 in the diagram].
If we consider Ocean as Internet and island as private network (or LAN) of an organization then travelling via boat is same as connecting to a web server or any other network device through the internet. You have no control over traffic, wires and all other internet networking stuff. Just like you have no control over people present on other islands when you are in boat. This makes communication very risky and susceptible to security threats. Therefore connecting two network resources using public network is not at all a feasible option.
Case 2 -
Another option to build private and secure travel between islands is to build the bridge between them. This will provide easy, fast and secure way of travel. However, building bridge is expensive especially when distance between islands is high [Please see route number 2 in the diagram].
Bridge refers to implementing Leased Lines between network resources. The leased line provides a secure way of communication as it is dedicated to carry only specific network traffic. The leased lines are separate from Internet yet they can connect between two network endpoints and can provide secured communication. However, cost involved in leased line is pretty higher.
This is where VPN comes in picture.
Case 3 -
Instead of Bridge and boat, if you use submarines; your problem will be solved. Submarine will use Ocean only to travel yet other people can’t see inside submarine and privacy maintained. You will be hidden from other outside entities. Hence using submarine is fast, reliable, secured and cost effective as compared to building bridge. [Please see route number 3 in the diagram].
Here submarines refer to implementation of VPN. VPN is network which uses public infrastructure of internet to provide communication to remote locations.
VPN is fast, secured and reliable. Even if VPN works over internet all the information is transferred between network resources securely. VPN can grow or expand easily as compared to leased lines. This improves the productivity of remote located employees drastically.
More importantly VPN offers you Security, Reliability and Scalability. Cost is reduced as it does not require physical lines to connect to remote locations. VPN offers you a way of cryptographic tunneling protocols to provide confidentiality and authentication block to avoid identity risks.
VPN offers remote end user an experience of accessing main organization network as if he is working within organization network boundary.
Hope above article gives you idea of VPN.