What Is a VPN? A Manual for Dummies

What is a VPN?

A VPN (Virtual Private Network) is a technology that allows you to make one or more connections over a third-party network (such as the Internet).

A VPN enables multiple departments (offices) to be combined to create a single network. Data packets are broadcast over a public network, much like in a two-point connection. Using a VPN helps to ensure the integrity and security of the information transmitted when interacting with multiple networks. The technology also avoids the mismatch of addressing schemes.

Characteristics of a virtual private network

As in the case of setting up dial-up connections, a VPN involves exchanging data using the PPP protocol. However, the fundamentally important thing is the transmission of the data using a secure tunnel.

To create a VPN, an encapsulation method of various types of protocols is used, followed by conversion to a PPP. Next, a new encapsulation takes place, and the IP becomes its logical continuation (less commonly, ATM or FR).

Alternatively, the procedure can be performed with network protocol packets to form, for example, VTP or any other tunneling protocol. Such methods are called Layer 2 or 3 tunneling accordingly.

Thus, one protocol will be used to organize the connection, while the other will serve to encapsulate information in order to further transmit data through the tunnel.

VPN structure features

A VPN includes internal and external networks. The first is called a controlled one, and it can consist of several networks at the same time. An encapsulation is carried out over the second network (usually, it’s the Internet).

The scheme for connecting a user to a VPN network is simple and is implemented through an access server acting as an intermediary between internal and external networks. While connecting, the server will require identification data and will authenticate the user. As a result, the user of the remote network will be authorized to work.

Security and protection

By the degree of protection, VPN networks are divided into:

• Secured. They are characterized by reliability, and the connection is carried out based on the Internet. The most common networks of this type include OpenVPN and IPsec.
• Trusted. As a rule, they are used in more reliable transmission networks than the Internet. With their help, you can create a virtual subnet. Trusted VPNs include MPLS and L2TP.

The use of trusted VPN networks is supported by secure ones, for example, L2TP and IPsec.

Implementation of a VPN network can be carried out both thanks to hardware-software and purely software solutions. In the first case, maximum performance and increased security are provided. The second option is relatively easy to implement since it involves the use of a personal computer with specialized software.

An alternative to the two implementation methods mentioned above is an integrated solution. Within this option, a complex is used to ensure traffic filtering in the network (Firewall).

Types of VPN networks by purpose:

• Intranet VPN is used to set up a secure network with the connection of users exchanging information via open channels. Suitable for several divisions of the same company.
• Remote Access allows you to create a secure channel between the main segment and the remote user. Suitable for remote employees who use specialized services of the company.
• Extranet VPN is used with customers with a lower level of trust than members of the internal network. One of Extranet’s features is a Firewall that protects confidential data.