Types of VPN Protocols

A protocol is a set of standardized rules that determines error detection methods, data authentication, signaling and representation of data over a communications channel the medium used for the transfer of data from the sender to the receiver. Its purpose is to ensure a reliable channel for the exchange of data. Virtual Private Network technology is heavily influenced by tunneling, which is the process of creating and maintaining logical network connection or ‘tunnels’ with the help of public internet.

Once we have decided to use the VPN service we further have to decide what type of VPN protocols to use. There are a number of VPN protocols in use that secure the transport of data traffic over a public network infrastructure. The most used VPN protocols are: PPTP, L2TP, IPSec, SSL.

PPTP

Point-to-Point Tunneling Protocol (PPTP) is a networking protocol that is built on the Point-to-Point (PPP) protocol. PPTP is one of the most widely used VPN protocols because of its simple configuration and easy maintenance and also because it is included with the Windows operating system. Its main function is to ensure that data from one VPN computer, or node, to another is transmitted securely. The PPTP also supports VPN over public networks like the Internet. It was created by Microsoft in association with other technology companies. But compared to other methods, PPTP is faster and it is also available for Linux and Mac users.

L2TP

L2TP (Layer 2 Tunneling Protocol) is another tunneling protocol that supports VPNs. This was developed as a joint effort between Microsoft and Cisco Systems. The Layer Two Forwarding protocol (L2F) is the Cisco Systems equivalent of the Microsoft-based PPTP protocol. In an attempt to improve on L2F, the best features of it and PPTP were combined to create a new standard called L2TP. Alongside providing data confidentiality as in PPTP, L2TP also allows data integrity that is the protection of data against its customization between the times it takes to reach from sender to receiver. It requires a digital certificate or a shared key for its implementation and is available as built-in feature in Windows.

IPSec

IPSec (IPSecurity) traffic can use either L2TP data packets transport mode or tunneling to encrypt data traffic in a VPN. The difference between the two modes is that transport mode encrypts only the message within the data packet (also known as the payload) while tunneling encrypts the entire data packet. IPSec is often referred to as a "security overlay" because of its use as a security layer for other protocols. IPSec can be expensive and time consuming client installations.

SSL

Secure Sockets Layer (SSL) and Transport Layer Security (TLS) use cryptography to secure communications over the Internet. SSL is a VPN accessible via https over web browser. The advantage of this SSL VPN is that it doesn’t need any software installed because it uses the web browser as the client application. Through SSL VPNs the user’s access can be restrict to specific applications instead of allowing access to the whole network.