Port Forwarding - ZyXEL Communications PMG5318-B20A User Manual

NAT Application
The following figure illustrates a possible NAT application, where three inside LANs (logical LANs
using IP alias) behind the GPON Device can communicate with three distinct WAN networks.
Figure 39 NAT Application With IP Alias
Corporation B
LAN2: 192.168.1.X
Network Server
"Admin=192.168.1.1
NAT Server
192.168.1.1
LAN2: 192.168.2.X
Network Server
"Sales"=192.168.2.1
NAT Server
192.168.2.1
LAN3: 192.168.3.X
Network Server
"R&D"=192.168.3.1
NAT Server
192.168.3.1

7.2 Port Forwarding

A port forwarding set is a list of inside (behind NAT on the LAN) servers, for example, web or FTP,
that you can make visible to the outside world even though NAT makes your whole inside network
appear as a single computer to the outside world.
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.
PMG5318-B20A User's Guide
Corporation A
Server in
Admin Network
=IP1 (IGA 1)
Internet
WAN Addresses: LAN Addresses: (Default IPs)
IGA 1 ---------------> 192.168.1.1
IGA 2 ---------------> 192.168.2.1
IGA 3 ---------------> 192.168.3.1
Chapter 7 NAT
Server in
Sales Network
=IP2 (IGA 2)
Server in
R&D Network
=IP3 (IGA 3)
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