ZyXEL Communications P-334W User Manual

Page of 496
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.