A VPN (Virtual Private Network) is a network technology that extends a private network over a public network such as the Internet. A VPN service enables a computer to communicate over a public network as if it were part of the private network, and in turn taking advantage of the benefits afforded by the private network such as security and functionality, among others.

A VPN connection over a public network such as the Internet works the same way as a wide area network (WAN) linking different sites. For this reason, VPNs are widely used to connect intranets of a company worldwide.

VPNs were previously a reserve for corporate organizations and companies and were used by their employees to provide secure remote access to the corporate intranet. However, nowadays, VPNs are used by individual Internet users to provide privacy, security, anonymity, and bypass censorships, among other uses.

All users need to be authenticated with unique login details before accessing a private network. Authentication typically entails a unique personal identification number (PIN) whose value changes based on a given frequency, say a couple of seconds.

What Is a VPN Tunnel?

When you connect a machine to a VPN (Virtual Private Network), the machine acts as if it were on the VPN’s local network. All your traffic is carried through a secure tunnel over a public network, enabling secure access to local network resources even though you’re physically in a different geographic location. This technology of creating a logical network connection is known as VPN tunneling.

A VPN tunnel is simply a secure connection between two machines or networks located in different places. Once a VPN tunnel is established, communication between the two endpoints only happens after authentication. Data traffic in the tunnel is encrypted and only the intended sender and receiver have access to the content. Evidently, this has many benefits, notably security for your data.

VPN tunneling is implemented through a set of protocols, including Point-to-Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP), and Internet Protocol Security (IPSec), among others. These three are among the most popular VPN tunneling protocols in use today and are generally incompatible with each other.

Type of the VPN Tunnel

VPN technology is used to create secure tunnels through which a computer sends and receives data over a public network. This is implemented through a set of VPN protocols, each one with its own unique way of creating the secure tunnel.

The most commonly applied VPN protocols include L2TP, IPSec, PPTP, SSL, and Open VPN.

L2TP (Layer 2 Tunneling Protocol) is used to create a secure tunnel for data transmission between two sites over a public network. It is typically used alongside IPSec (acting as a security layer) to securely transfer L2TP packets over the Internet. The implementation of L2TP requires the use of certificates or shared keys.

IPSec (IP Security) is used to provide secure data transfer over the Internet using either tunneling or transport layer for encryption. IPSec is often used as a security layer in other protocols.

PPTP (Point-To-Point Tunneling Protocol) is a protocol that securely connects a remote machine to a private network across a public network. PPTP has a simple setup and for this reason, it’s one of the most widely used VPN protocols. It’s also natively included in all Windows systems.

SSL (Secure Sockets Layer) – as well as TLS (Transport Layer Security) uses cryptography to create secure tunnels over the Internet. These protocols employ a ‘handshake’ method of authentication that entails negotiation of network parameters between server and client computers. Certificates (cryptographic keys residing on both the server and client machines) are used to start a connection.