ZyXEL Communications AMG1302 User Manual
Chapter 11 Network Address Translation (NAT)
AMG1302/AMG1202-TSeries User’s Guide
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11.3 The Port Forwarding Screen
Use this screen to forward incoming service requests to the server(s) on your local network.
You may enter a single port number or a range of port numbers to be forwarded, and the local IP
address of the desired server. The port number identifies a service; for example, web service is on
port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can
support more than one service (for example both FTP and web service), it might be better to
specify a range of port numbers. You can allocate a server IP address that corresponds to a port or
a range of ports.
address of the desired server. The port number identifies a service; for example, web service is on
port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can
support more than one service (for example both FTP and web service), it might be better to
specify a range of port numbers. You can allocate a server IP address that corresponds to a port or
a range of ports.
The most often used port numbers and services are shown in
to RFC 1700 for further information about port numbers.
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.
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.
server receives packets from ports that are not specified in this screen.
Note: If you do not assign a Default Server IP address, the AMG1302/AMG1202-TSeries
discards all packets received for ports that are not specified here or in the remote
management setup.
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.
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 67
Multiple Servers Behind NAT Example
11.3.1 Configuring the Port Forwarding Screen
Click Network Setting > NAT > Port Forwarding to open the following screen.
A=192.168.1.33
D=192.168.1.36
C=192.168.1.35
B=192.168.1.34
WAN
LAN
192.168.1.1
IP Address assigned by ISP