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ZyXEL Communications ZyXEL ZyWALL 5 User Manual

Page 248

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ZyWALL 5 User’s Guide

Chapter 14 VPN Screens

247

My ZyWALL

Enter the WAN IP address or domain name of your ZyWALL or leave the field set

to 0.0.0.0. The VPN tunnel has to be rebuilt if the My ZyWALL IP address changes

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

The ZyWALL uses the current ZyWALL WAN IP address (static or dynamic) to

set up the VPN tunnel.

If the WAN connection goes 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.

Remote Gateway

Addr

Type the WAN IP address or the domain name (up to 31 characters) of the IPSec

router with which you're making the VPN connection.

Manual Proposal

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.

Active Protocol

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).
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).

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.

Encryption Key

This field is applicable when you select ESP in the Active Protocol field above.
With DES, type a unique key 8 characters long. With 3DES, type a unique key 24

characters long. Any characters may be used, including spaces, but trailing spaces

are truncated.

Authentication

Key

Type a unique authentication key to be used by IPSec if applicable. Enter 16

characters for MD5 authentication or 20 characters for SHA-1 authentication. Any

characters may be used, including spaces, but trailing spaces are truncated.

Apply

Click Apply to save your changes back to the ZyWALL.

Cancel

Click Cancel to exit this screen without saving.

Table 72 VPN Rules (Manual) Edit (continued)

LABEL

DESCRIPTION