As promised, let me continue with my venture with VPN protocols. You will get to read a lot about different free VPN services around the Internet but hardly will people tell you how these VPN services function. It is when you understand the technicalities hidden behind these VPN services, that you are able to choose for the best VPN service for yourself. Learn about the L2TP protocol.

Other VPN protocols that I have already discussed (list will be updated as and when new articles are written):

NOTE: Remember to read these in the order given above so that you understand them more clearly.

Today, we will throw some light on the Layer 2 Tunneling Protocol which is also called L2TP in short. This protocol was created in coordination with the likes of Microsoft and Cisco. Layer 2 Tunneling Protocol was actually a combination of two different protocols given below:

  • Layer 2 Forwarding (L2F) protocol owned and developed by Cisco.
  • Point-to-Point tunneling protocol owned and developed by Microsoft.

L2TP had several advantages that made it shine when compared to PPTP. One of the most important of these advantages was its usage over non-IP networks such as frame relay, X.25, and ATM. L2TP, like PPTP, operates over the data link layer in the very famous OSI network model. Also, most of the major firewalls like WatchGuard, Cisco PIX, CheckPoint, and ISA server support L2TP without any hitches.

The Windows-based 2003, XP and 2000 carry the built-in client for L2TP. If you are one of the legacy Windows users who are still using older versions of Windows (like Windows 98, NT4.0 or ME) then you can download clients that support L2TP.

L2TP uses the features provided by IP Sec (IP security) and its enhanced form namely ESP (Encapsulating Security Payload) protocol to secure its connections. It also requires the use of digital certificates for security reasons. L2TP can perform user authentication using a similar technology that was used by PPTP – the PPP authentication mechanism. L2TP provides computer-based authentication which is not supported by PPTP. This is an extra security layer that is not present in PPTP.

Let us check out some more advantages of L2TP over PPTP:

  • PPTP gives data confidentiality but L2TP provides data integrity. Basically, it is the protection of data between its flight from sender to receiver.
  • Authentication of Origin which is quite self-explanatory. This feature confirms that the sender of data is the actual sender of data.
  • Replay protection which prevents the hacker from capturing the data after it is released from its origin. Hackers usually capture the data during its flights and edit it before it reaches its destination. This is prevented by this new feature of L2TP.
  • It may use Perfect Forward Secrecy (PFS).

One must understand that L2TP might look a slow protocol when compared to PPTP because it provides extra features that are not present in PPTP.