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What is Virtual private network and how it works

May 18, 2018
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VPN literally stands for virtual private network. With a VPN, all your traffic is held inside a private, encrypted tunnel as it makes its way through the public internet. You don’t access the destination until after you’ve reached the end of the VPN tunnel. The root of why VPNs are popular is because they can be used to anonymize and encrypt internet traffic. Governments, ISPs, wireless network hackers and others can not only not see what’s inside a VPN but also usually not even be able to find out who is using it.

Overview of VPN

A virtual private network, or VPN, is an encrypted connection over the Internet from a device to a network. The encrypted connection helps ensure that sensitive data is safely transmitted. It prevents unauthorized people from eavesdropping on the traffic and allows the user to conduct work remotely.  VPN technology is widely used in corporate environments.

A Virtual Private Network (VPN) is an entity where remote locations are connected over a shared provider environment. It establishes connectivity between a set of geographically dispersed endpoints in a network infrastructure. The endpoints of the VPN are connected using links and increasing demand on the performance of network connectivity augur reliable network connections.

The VPNs are primarily used in improvised domains that do not require any fixed infrastructure. Each node in the network serves as a host and performs the role of a router as well. The node sends and receives its data packet in addition to relaying those of other nodes to reach their destinations. The network is seen to inherit a variable topology on account of the movement of its nodes and the absence of a control center to support its configuration. A VPN reaches out to emulate the services provided by a private network in the interest of addressing the rising service concerns. It offers customers with predictable and safe network connections over a public network. However the growing number of supported VPNs increases the operational complexity and cost for a service provider. Following diagram shows the view of virtual private network.

Virtual Private Network

Why we used VPN?

As a business grows, it might expand to multiple shops or offices across the country and around the world. To keep things running efficiently, the people working in those locations need a fast, secure and reliable way to share information across computer networks. In addition, traveling employees like salespeople need an equally secure and reliable way to connect to their business’s computer network from remote locations. One popular technology to accomplish these goals is a VPN (virtual private network). A VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. The VPN uses “virtual” connections routed through the Internet from the business’s private network to the remote site or employee. By using a VPN, businesses ensure security — anyone intercepting the encrypted data can’t read it.

Components to Setup VPN

  1. Authentication, 2. Tunneling, 3. Encryption

Authentication: Tunnel endpoints must be authenticated before secure VPN tunnels can be established. User created remote-access VPNs may use passwords, biometrics, two-factor authentication or other cryptographic methods. Network-to-network tunnels often use passwords or digital certificates. They permanently store the key to allow the tunnel to establish automatically, without intervention from the user.

Tunneling: Virtual private network technology is based on the idea of tunneling. VPN tunneling involves establishing and maintaining a logical network connection (that may contain intermediate hops). On this connection, packets constructed in a specific VPN protocol format are encapsulated within some other base or carrier protocol, then transmitted between VPN client and server, and finally de-encapsulated on the receiving side. VPN supports two types of tunneling – voluntary and compulsory. Both types of tunneling are commonly used.

VPN Tunneling Protocols: Several computer network protocols have been implemented specifically for use with VPN tunnels.

Limitations of a VPN

Despite their popularity, VPNs are not perfect and limitations exist as is true for any technology. Organizations should consider issues like the below when deploying and using virtual private networks in their operations:

  • VPNs require detailed understanding of network security issues and careful installation/configuration to ensure sufficient protection on a public network like the Internet.
  • The reliability and performance of an Internet-based VPN is not under an organization’s direct control. Instead, the solution relies on an ISP and their quality of service.
  • Historically, VPN products and solutions from different vendors have not always been compatible due to issues with VPN technology standards. Attempting to mix and match equipment may cause technical problems, and using equipment from one provider may not give as great a cost savings.

Types of VPNs

Remote access

A remote access VPN securely connects a device outside the corporate office. These devices are known as endpoints and may be laptops, tablets, or smartphones. Advances in VPN technology have allowed security checks to be conducted on endpoints to make sure they meet a certain posture before connecting. Think of remote access as computer to network.


A site-to-site VPN connects the corporate office to branch offices over the Internet. Site-to-site VPNs are used when distance makes it impractical to have direct network connections between these offices. Dedicated equipment is used to establish and maintain a connection. Think of site-to-site access as network to network.


[1] “Chapter 1: Introduction”, available online at:

[2] Saugat Bhattarai, “Virtual Private Network”, January 2016

[3] “What Is a VPN?” available online at:

[4] Melanie Pinola, available online at:


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