ZyXEL 2WG Guida Utente

Chapter 18 Network Address Translation (NAT) Screens

ZyWALL 2WG User’s Guide

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If you do not assign a Default Server IP address, the ZyWALL discards all 
packets received for ports that are not specified here or in the remote 
management setup.

The ZyWALL provides the additional safety of the DMZ ports for connecting your publicly 
accessible servers. This makes the LAN more secure by physically separating it from your 
public servers. 
Use the Port Forwarding screen to forward incoming service requests to the server(s) on your 
local network.
The most often used port numbers are shown in the  appendix on

. Please refer to 

RFC 1700 for further information about port numbers.

Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (A in the 
example), port 80 to another (B in the example) and assign a default server IP address of 
192.168.1.35 to a third (C in the example). You assign the LAN IP addresses and the ISP 
assigns the WAN IP address. The NAT network appears as a single host on the Internet.

Figure 242   Multiple Servers Behind NAT Example

The ZyWALL has two WAN interfaces. You can configure port forwarding and trigger port 
rule sets for the first WAN interface and separate sets of rules for the second WAN interface.