The Basics of Virtual Private Networks


If there’s one important advancement made on the Internet, it’s the virtual private network or simply called VPN. By definition, the VPN is a private network that utilizes the Internet to connect to users and remote sites.

If, for example, you own a business in various cities, you can use the VPN to efficiently manage your people who are working in different locations. Of course, a fast and secure Internet connection is necessary to achieve this.

What’s probably the most important feature of the VPN is security. As its name suggests, the VPN utilizes a virtual connection that is routed through the web from the company’s private network to the employee or remote site. Anybody trying to intercept an encrypted data can’t, therefore, read it.


Here are the two types of VPNs:

Remote Access

Also referred to as a Virtual Private Dial-up Network or VPDN, this is commonly used by companies who have remote employees who need to establish a connection to private networks. This user-to-LAN connection offers an encrypted connection between the user and the company’s private network. This is often accomplished through a third-party service provider.

Site to Site

A company may connect to various fixed sites over a public network such as the world wide web. A website merely needs a local connection to the same public network. This helps them save more money on long private leased lines.

What are the features of a well-designed VPN?

  • Network management
  • Policy management
  • Reliability
  • Scalability
  • Security

What benefits can companies get from a well-structured VPN?

  • Deliver faster return on investment (ROI) than traditional WAN
  • Enhance productivity
  • Extend geographic connectivity
  • Give telecommuter support
  • Minimize operational costs versus traditional WANs
  • Offer global networking opportunities
  • Reduce transit times and traveling expenses for remote users
  • Simplify network topology

Related: How Virtual Private Network Works?

What does a well-designed VPN use to keep data and connection secure?


Confidentiality of data

What’s probably the most important benefit that one gets from the VPN is data confidentiality. By encrypting data, information sent from one computer to another is encoded into a form that only a computer can decode.

The most-used encryption protocols nowadays are:

  • Internet Protocol Security Protocol (IPsec)
  • Layer 2 Tunneling Protocol (L2TP)/IPsec
  • PPTP/Microsoft Point-to-Point Encryption (MPPE)

Integrity of data

Most encryption protocols have a way of ensuring that the encrypted data are not changed while in transit. If tampering of data is detected, the encryption protocol will drop the packet.

searchAuthentication of data origin

The identity of a data source needs to be verified to prevent Internet attacks.


VPNs may detect and refuse replayed packets. It likewise helps avoid spoofing.

Data tunneling

By definition, tunneling is a process of encapsulating a packet with another packet and sending it over a network. It is a helpful process in cases where the identity of a device originating the traffic needs to be hidden.

How Virtual Private Network Works?


When your business matures, the network might spread out from corner to corner in the country and/or across the world. For things to run efficiently, you must need a secure, durable, and fast way of connection to share all the information with people across the computer network. In addition to that, your nomadic employees such as salespeople require an equally durable and secure connection to hook up to their business’s system network from distant and remote locations.

Virtual Private Network (VPN) is one powerful technology to bring about this goal. VPN is the private network that employs the public network (generally the Internet) to join distant users or sites together. It utilizes ‘virtual’ links routed via the Internet from your company’s private network or connection to the distant employees or sites. VPN ensures your business’s security as anyone who captures your encrypted data will be unable to read it.

An archetypal VPN has the central LAN i.e., local-area network at the company’s headquarters, further LANs at distant facilities or offices, and individual mobile users that may connect or join from outside in the fields. VPNs are of two types.


It is also known as VPDN i.e., Virtual Private Dial-up Network. It is the connection from user-to-LAN. This network is used by the organizations that have workers and employees who require joining to the private network from different remote locations. Characteristically, the organization that wants to use a large remote-access network needs to provide Internet dial-up account to its consumers and users who employ an ISP i.e., Internet Service Provider. This is how the telecommuters become able to dial the 1-800 number as to access the Internet and utilize their VPN punter software to have the access to the company’s network. The remote-access VPN allows encrypted and secure connections between the remote users and organization’s private network by means of the third-party service supplier.


The Site-to-Site connections permit branch and division offices to employ the Internet as the channel to access the main company office’s intranet. This connection expands the organization’s network, making the fixed location computer resources, available to workers at other sites. A rising organization with several branch offices needs this VPN connection.


VPN Products

There are certain components need to set up to construct your VPN. These includes:

  1. Desktop software punter for every remote or mobile user
  2. Devoted hardware like VPN Cisco Concentrator or Cisco Secure PIX Firewall
  3. Devoted VPN server for services like dial-up
  4. NAS, i.e., Network Access Server that is employed by service provider for having the access to distant users
  5. Policy managing center and a private network

Because the broadly accepted protocol to implement the VPN is missing, many corporations have built key solution all by themselves. For instance, Cisco provides various VPN solutions including:

VPN Concentrator

Cisco-VPN concentrator is specifically built to create a site-to-site or remote access VPN and preferably arranged where the necessity is the single piece of equipment to hold an outsized number of VPN tunnels. It incorporates the most sophisticated authentication and encryption techniques present at the moment. These concentrators present high scalability, high performance, and availability and involve components, known as SEP i.e., Scalable Encryption Processing modules. It permits users to easily elevate capacity.

VPN-Optimized Router

Every Cisco router that runs Cisco-IOS software holds up IPsec VPNs. The only necessity is that a Cisco IOS image is must run by the router with the suitable feature set. This VPN solution completely supports the distant and remote access, extranet and intranet VPN necessities. It indicates that Cisco router performs just as well whether connected to the VPN device like the router and VPN Concentrator or when attached to the distant host running the VPN Client’s software.

Cisco VPN Clients

Cisco offers software as well as hardware VPN clients. With no extra cost, the software Cisco VPN Client comes along with the 3000 series concentrator of Cisco VPN. This can easily be inserted into the host device and employed to securely connect to the fundamental site concentrator or to any VPN device like firewall or router.

The selection of equipment that you use to put up VPN solution is eventually the design subject that depends on a variety of factors such as the number of clients/users and the preferred throughput.