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2 esp (encapsulating security payload) protocol, 3 my ip address, Table 59 ah and esp – ZyXEL Communications ADSL VoIP IAD with 802.11g Wireless 2602HW Series User Manual

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Prestige 2602HW Series User’s Guide

202

Chapter 17 VPN Screens

17.2.2 ESP (Encapsulating Security Payload) Protocol

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.

17.3 My IP Address

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 59 AH and ESP

ESP

AH

ENCRYPTION

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.

AUTHENTICATION

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.