Port Forwarding: Services And Port Numbers; Configuring Servers Behind Port Forwarding (Example); Nat And Multiple Wan; Figure 254 Multiple Servers Behind Nat Example - ZyXEL Communications 5 Series User Manual

Chapter 22 Network Address Translation (NAT)
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.

22.4.2 Port Forwarding: Services and Port Numbers

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 User's Guide appendix
page 783. Please refer to RFC 1700 for further information about port numbers.

22.4.3 Configuring Servers Behind Port Forwarding (Example)

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 254 Multiple Servers Behind NAT Example

22.4.4 NAT and Multiple WAN

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.
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Appendix B on
ZyWALL 5/35/70 Series User's Guide