L2TP
Some Background.
L2TP - Layer 2 Tunneling Protocol is a tunneling
protocol that operates at layer 2 of the OSI model. It was
developed by Cisco, largely to combat what Cisco considered to be
deficiencies in PPTP. Their initial effort resulted in the L2F - Layer 2 Forwarding protocol. Unfortunately, L2F provided encapsulation, but didn't encrypt what was being encapsulated. In order to make use of the features of both PPTP and L2F, L2TP was developed in a joint venture between Microsoft and Cisco. L2TP was definitely an improvement. L2TP does not provide its own internal encryption capabilities. But L2TP was developed to make sue of IPSec for encryption among other things. The main differences between PPTP and L2TP are listed in the following table. |
Differences Between PPTP and L2TP | |
PPTP | L2TP |
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One of the most common mistakes made when
implementing VPNs using PPTP or L2TP is to forget to allow the
associated ports through the firewall.
Microsoft supports L2TP in Windows 2000 and after. But because of the computing resources required by implementing L2TP, most implementations make use of specialized hardware. More will be added. |