Nat Port Forwarding Example - ZyXEL Communications NBG-416N User Manual

Chapter 10 Network Address Translation
In addition to the servers for specified services, NAT supports a default server. A
service request that does not have a server explicitly designated for it is forwarded
to the default server. If the default is not defined, the service request is simply
discarded.
Note: Many residential broadband ISP accounts do not allow you to run any server
processes (such as a Web or FTP server) from your location. Your ISP may
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.

10.5.2 NAT 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 76 Multiple Servers Behind NAT Example
118
NBG-416N User's Guide