ZyXEL Communications P-334W - Manual (Page 211)

Prestige 334W User’s Guide
VPN Screens 16-1
Chapter 16
VPN Screens
This chapter introduces the VPN Web Configurator. See the Logs chapter for information on
viewing logs and the Appendices for IPSec log descriptions.
16.1 VPN/IPSec Overview
Use the screens documented in this chapter to configure rules for VPN connections and manage VPN
connections.
16.2 IPSec Algorithms
The ESP and AH protocols are necessary to create a Security Association (SA), the foundation of an IPSec
VPN. An SA is built from the authentication provided by the AH and ESP protocols. The primary function
of key management is to establish and maintain the SA between systems. Once the SA is established, the
transport of data may commence.
16.2.1 AH (Authentication Header) Protocol
AH protocol (RFC 2402) was designed for integrity, authentication, sequence integrity (replay resistance),
and non-repudiation but not for confidentiality, for which the ESP was designed.
In applications where confidentiality is not required or not sanctioned by government encryption
restrictions, an AH can be employed to ensure integrity. This type of implementation does not protect the
information from dissemination but will allow for verification of the integrity of the information and
authentication of the originator.