ZyXEL Communications ZyWALL5UTM 4.0 User Manual

ZyWALL 5/35/70 Series User’s Guide

Chapter 19 VPN Screens

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Figure 158   Telecommuters Sharing One VPN Rule Example

Table 108   Telecommuters Sharing One VPN Rule Example

My ZyWALL: 

0.0.0.0 (dynamic IP address 

assigned by the ISP)

Public static IP address 

Remote Gateway 

Address:

Public static IP address

0.0.0.0        With this IP address only 

the telecommuter can initiate the 

IPSec tunnel.

Local Network - Single 

IP Address: 

Telecommuter A: 192.168.2.12
Telecommuter B: 192.168.3.2
Telecommuter C: 192.168.4.15

192.168.1.10

Remote Network -  

Single IP Address:

192.168.1.10

Not Applicable 

In this example the telecommuters (A, B and C in the figure) use IPSec routers with domain 
names that are mapped to their dynamic WAN IP addresses (use Dynamic DNS to do this).

With aggressive negotiation mode (see 

), the ZyWALL can use the 

ID types and contents to distinguish between VPN rules. Telecommuters can each use a 
separate VPN rule to simultaneously access a ZyWALL at headquarters. They can use 
different IPSec parameters. The local IP addresses (or ranges of addresses) of the rules 
configured on the ZyWALL at headquarters can overlap. The local IP addresses of the rules 
configured on the telecommuters’ IPSec routers should not overlap.

See the following table and figure for an example where three telecommuters each use a 
different VPN rule for a VPN connection with a ZyWALL located at headquarters. The 
ZyWALL at headquarters (HQ in the figure) identifies each incoming SA by its ID type and 
content and uses the appropriate VPN rule to establish the VPN connection. 

The ZyWALL at headquarters can also initiate VPN connections to the telecommuters since it 
can find the telecommuters by resolving their domain names.