ZyXEL Communications ZyXEL ZyWALL 2WE - Manual (Page 321)

ZyWALL 2 and ZyWALL 2WE
VPN/IPSec Setup 27-27
27.16 Telecommuter VPN/IPSec Examples
The following examples show how multiple telecommuters can make VPN connections to a single ZyWALL
at headquarters from remote IPSec routers that use dynamic WAN IP addresses.
27.16.1 Telecommuters Sharing One VPN Rule Example
Multiple telecommuters can use one VPN rule to simultaneously access a ZyWALL at headquarters. They
must all use the same IPSec parameters (including the pre-shared key) but the local IP addresses (or ranges of
addresses) cannot overlap. See the following table and figure for an example.
Having everyone use the same pre-shared key may create a vulnerability. If the pre-shared key is
compromised, all of the VPN connections using that VPN rule are at risk. A recommended alternative is to
use a different VPN rule for each telecommuter and identify them by unique IDs (see section 27.16.2 for an
example)
Table 27-12 Telecommuter and Headquarters Configuration Example
TELECOMMUTER HEADQUARTERS
My IP Address: 0.0.0.0 (dynamic IP address
assigned by the ISP) Public static IP address
Secure Gateway
IP Address: Public static IP address or domain
name. 0.0.0.0 With this IP address only the
telecommuter can initiate the IPSec tunnel.