ZyXEL Communications prestige 2602h series User Manual

Prestige 2602H/HW Series User’s Guide

214

Chapter 17 VPN Screens

The ESP protocol (RFC 2406) provides encryption as well as the services offered by AH. ESP 
authenticating properties are limited compared to the AH due to the non-inclusion of the IP 
header information during the authentication process. However, ESP is sufficient if only the 
upper layer protocols need to be authenticated.

An added feature of the ESP is payload padding, which further protects communications by 
concealing the size of the packet being transmitted.

My IP Address is the WAN IP address of the Prestige. The Prestige has to rebuild the VPN 
tunnel if the My IP Address changes after setup.

The following applies if this field is configured as 0.0.0.0:

• The Prestige uses the current Prestige WAN IP address (static or dynamic) to set up the 

VPN tunnel. 

Table 66   AH and ESP

DES (default)
Data Encryption Standard (DES) is a widely 

used method of data encryption using a 

private (secret) key. DES applies a 56-bit key 

to each 64-bit block of data.

MD5 (default)
MD5 (Message Digest 5) produces a 128-bit 

digest to authenticate packet data.

3DES
Triple DES (3DES) is a variant of DES, which 

iterates three times with three separate keys 

(3 x 56 = 168 bits), effectively doubling the 

strength of DES.

SHA1
SHA1 (Secure Hash Algorithm) produces a 

160-bit digest to authenticate packet data.

AES
Advanced Encryption Standard is a newer 

method of data encryption that also uses a 

secret key. This implementation of AES 

applies a 128-bit key to 128-bit blocks of data. 

AES is faster than 3DES.

Select NULL to set up a phase 2 tunnel 

without encryption.

MD5 (default)
MD5 (Message Digest 5) produces a 128-bit 

digest to authenticate packet data.

MD5 (default)
MD5 (Message Digest 5) produces a 128-bit 

digest to authenticate packet data.

SHA1
SHA1 (Secure Hash Algorithm) produces a 

160-bit digest to authenticate packet data.

SHA1
SHA1 (Secure Hash Algorithm) produces a 

160-bit digest to authenticate packet data.

Select MD5 for minimal security and SHA1 for maximum security.