The Virtual Server Screen; Configuring Servers Behind Port Forwarding (Example); Figure 36 Multiple Servers Behind Nat Example; Table 23 Multiple Servers Behind Nat Example - ZyXEL Communications P-660R User Manual

Chapter 10 Network Address Translation (NAT)

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 ZyXEL Device 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
refer to RFC 1700 for further information about port numbers.
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

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

A
B
C
84
LAN
A=192.168.1.33
192.168.1.1
SERVERS
FTP
Telnet
SMTP
Appendix D on page
WAN
IP Address assigned by ISP
PORTS DEFAULT SERVER IP
21-22 192.168.1.33
23 192.168.1.34
25 192.168.1.35
P-660R-Tx v3 User's Guide
205. Please