ZyXEL Communications 2 Plus User Manual

 Chapter 14 IPSec VPN

ZyWALL 2 Plus User’s Guide

In the web configurator, click SECURITY > VPN > SA Monitor. Use this screen to display 
and manage active VPN connections.
A Security Association (SA) is the group of security settings related to a specific VPN tunnel. 
This screen displays active VPN connections. Use Refresh to display active VPN 
connections. 

Primary Remote 

Gateway

Type the WAN IP address 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   SECURITY > VPN > VPN Rules (Manual) > Edit (continued)