ZyXEL Communications Internet Security Gateway ZyWALL 2 Series User Manual page 513

FIELD
NAT Traversal Select this check box to enable NAT traversal. NAT traversal allows you to
set up a VPN connection when there are NAT routers between the two
IPSec routers.
The remote IPSec router must also have NAT traversal enabled. You can
use NAT traversal with ESP protocol using Transport or Tunnel mode,
but not with AH protocol nor with Manual key management.
In order for an IPSec router behind a NAT router to receive an initiating
IPSec packet, set the NAT router to forward UDP port 500 to the IPSec
router behind the NAT router.
Local ID type Press [SPACE BAR] to choose IP, DNS, or E-mail and press [ENTER].
Select IP to identify this ZyWALL by its IP address.
Select DNS to identify this ZyWALL by a domain name.
Select E-mail to identify this ZyWALL by an e-mail address.
Content When you select IP in the Local ID type field, type the IP address of your
computer in the local Content field. The ZyWALL automatically uses the IP
address in the My IP Address field (refer to the My IP Address field
description) if you configure the local Content field to 0.0.0.0 or leave it
blank.
It is recommended that you type an IP address other than 0.0.0.0 in the
local Content field or use the DNS or E-mail ID type in the following
situations.
When you select DNS or E-mail in the Local ID type field, type a domain
name or e-mail address by which to identify this ZyWALL in the local
Content field. Use up to 31 ASCII characters including spaces, although
trailing spaces are truncated. The domain name or e-mail address is for
identification purposes only and can be any string.
My IP Addr Enter the IP address of your ZyWALL. The ZyWALL uses its current WAN
IP address (static or dynamic) in setting up the VPN tunnel if you leave this
field as 0.0.0.0.
The VPN tunnel has to be rebuilt if this IP address changes.
VPN/IPSec Setup
Table 37-2 Menu 27.1.1: IPSec Setup
DESCRIPTION
When there is a NAT router between the two IPSec routers.
When you want the remote IPSec router to be able to distinguish
between VPN connection requests that come in from IPSec
routers with dynamic WAN IP addresses.
ZyWALL 2 Series User's Guide
EXAMPLE
No
0.0.0.0
37-7