VPN Protocols

Most VPN systems use one of two main protocols: Point-to-Point Tunneling Protocol (PPTP) or IP Security (IPSec). IPSec is the more widely used protocol for VPNs. Other VPN systems use varying degrees of both protocols. Additionally, Microsoft and Cisco jointly developed another VPN protocol called Layer Two Tunneling Protocol (L2TP).

PPTP

Point-to-Point Tunneling Protocol was originally designed and developed by a consortium of companies to encapsulate non-TCP/IP protocols such as IPX over the Internet using Generic Routing Encapsulation (GRE). Security in the protocol was added later.

GENERIC ROUTING ENCAPSULATION

Many protocols are currently available that are designed to encapsulate or hide one protocol in another, normally ...

Get Linux Firewalls, Third Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.