The Virtual Server Screen; Configuring Servers Behind Port Forwarding (Example) - ZyXEL Communications AMG1001-T Series User Manual

10.4 The Virtual Server Screen

LAN computers usually have DHCP-assigned private IP address that cannot be accessed directly
from the WAN. Use this screen to allow the AMG1001-T/AMG1011-T to forward traffic to the servers
on the LAN.
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.
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.

10.4.1 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 36 Multiple Servers Behind NAT Example
A=192.168.1.33
B=192.168.1.34
C=192.168.1.35
The following table summarizes the settings described in the above example.
Table 23 Multiple Servers Behind NAT Example
SERVERS
A FTP
B Telnet
C SMTP
AMG1001-T/AMG1011-T Series User's Guide
LAN
192.168.1.1
PORTS DEFAULT SERVER IP
21-22 192.168.1.33
23 192.168.1.34
25 192.168.1.35
Chapter 10 Network Address Translation (NAT)
Appendix D on page
WAN
IP Address assigned by ISP
173. Please refer
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