ZyXEL Communications ZyXEL ZyWALL 35 User Manual

Page 263

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ZyWALL 35 User’s Guide

Chapter 14 VPN Screens

261

My Address

IP Address identifies the WAN IP address of the ZyWALL. You can select IP

Address and enter the ZyWALL's static WAN IP address (if it has one) or leave the

field set to 0.0.0.0. The VPN tunnel has to be rebuilt if the My Address changes

after setup.
The following applies if the My Address field is configured as 0.0.0.0:

When the WAN port operation mode is set to Active/Passive, the ZyWALL uses

the IP address (static or dynamic) of the WAN port that is in use.

When the WAN port operation mode is set to Active/Active, the ZyWALL uses

the IP address (static or dynamic) of the primary (highest priority) WAN port to

set up the VPN tunnel as long as the corresponding WAN1 or WAN2

connection is up. If the corresponding WAN1 or WAN2 connection goes down,

the ZyWALL uses the IP address of the other WAN port.

If both WAN connections go down, the ZyWALL uses the dial backup IP

address for the VPN tunnel when using dial backup or the LAN IP address

when using traffic redirect. See the chapter on WAN for details on dial backup

and traffic redirect.

Select My Domain Name and choose one of the dynamic domain names that you

have configured (in the DDNS screen) to have the ZyWALL use that dynamic

domain name's IP address.

Secure Gateway

Addr

Type the WAN IP address or the URL (up to 31 characters) of the IPSec router with

which you're making the VPN connection.

IPSec Property

SPI

Type a unique SPI (Security Parameter Index) from one to four characters long.

Valid Characters are "0, 1, 2, 3, 4, 5, 6, 7, 8, and 9".

Encapsulation

Mode

Select Tunnel mode or Transport mode from the drop-down list box.

ESP

Select ESP if you want to use ESP (Encapsulation Security Payload). The ESP

protocol (RFC 2406) provides encryption as well as some of the services offered

by AH. If you select ESP here, you must select options from the Encryption

Algorithm and Authentication Algorithm fields (described next).

Encryption

Algorithm

Select DES, 3DES or NULL from the drop-down list box.
When DES is used for data communications, both sender and receiver must know

the Encryption Key, which can be used to encrypt and decrypt the message or to

generate and verify a message authentication code. The DES encryption algorithm

uses a 56-bit key. Triple DES (3DES) is a variation on DES that uses a 168-bit key.

As a result, 3DES is more secure than DES. It also requires more processing

power, resulting in increased latency and decreased throughput. Select NULL to

set up a tunnel without encryption. When you select NULL, you do not enter an

encryption key.

Authentication

Algorithm

Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and

SHA1 (Secure Hash Algorithm) are hash algorithms used to authenticate packet

data. The SHA1 algorithm is generally considered stronger than MD5, but is

slower. Select MD5 for minimal security and SHA-1 for maximum security.

AH

Select AH if you want to use AH (Authentication Header Protocol). The 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. If you select AH here, you must select options from the Authentication

Algorithm field (described next).

Authentication

Algorithm

Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and

SHA1 (Secure Hash Algorithm) are hash algorithms used to authenticate packet

data. The SHA1 algorithm is generally considered stronger than MD5, but is

slower. Select MD5 for minimal security and SHA-1 for maximum security.

Table 79 VPN Manual Setup

LABEL

DESCRIPTION

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