What are the protocols behind IPSec?
The term IPSec actually covers a series of protocols used to send authenticated and/or encrypted data over IP networks. Roughly speaking, the protocols fall into three categories: encapsulating security payload (ESP) and authentication header (AH), which define encryption and authentication methods for IP payloads; and the IP security association key management protocol (ISAKMP), which manages the exchange of secret keys between senders and recipients of ESP or AH packets. AH provides authentication, integrity, and replay protection but not encryption and, unlike ESP, also secures parts of the IP header of the packet (such as the source/destination addresses). However, ESP provides privacy of the data by securing everything in the packet that follows the header. Encryption can be used orthogonally to authentication/integrity, and vice versa. What about PPTP? PPTP is an open documented standard published by the Internet Engineering Task Force (IETF) as RFC 2637 ftp://ftp.ietf.org/rfc/rf
