ZyXEL Communications P-2602HWLNI, User Manual, Page: 160 / 496

Chapter 10 Network Address Translation (NAT) Screens
P-2602HWLNI User’s Guide
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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.
10.4.1 Default Server IP Address
In addition to the servers for specified services, NAT supports a default server IP address. A
default server receives packets from ports that are not specified in this screen.
"
If you do not assign a Default Server IP address, the ZyXEL Device discards
all packets received for ports that are not specified here or in the remote
management setup.
10.4.2 Port Forwarding: Services and Port Numbers
Use the Port Forwarding screen to forward incoming service requests to the server(s) on your
local network.
The most often used port numbers and services are shown in
Appendix E on page 475 . Please
refer to RFC 1700 for further information about port numbers.
10.4.3 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 92 Multiple Servers Behind NAT Example