Chapter 9 The NAT Configuration Screens
User’s Guide
94
The following table describes the labels in this screen.
9.3 Port Forwarding
A NAT server set is a list of inside (behind NAT on the LAN) servers, for example, web or
FTP, that you can make accessible to the outside world even though NAT makes your whole
inside network appear as a single machine to the outside world.
Use the ADVANCED > NAT Configuration > Port Forwarding 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.
In addition to the servers for specified services, NAT supports a default server. A service
request that does not have a server explicitly designated for it is forwarded to the default
server. If the default is not defined, the service request is simply discarded.
For 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.
Table 33 ADVANCED > NAT Configuration > General
LABEL DESCRIPTION
Enable Network
Address Translation
Select this if you want to use port forwarding, trigger ports, or any of the
ALG.
Max NAT/Firewall
Session Per User
When computers use peer to peer applications, such as file sharing
applications, they may use a large number of NAT sessions. If you do
not limit the number of NAT sessions a single client can establish, this can
result in all of the available NAT sessions being used. In this case, no
additional NAT sessions can be established, and users may not be able to
access the Internet.
Each NAT session establishes a corresponding firewall session. Use this
field to limit the number of NAT/firewall sessions each client computer can
establish through the WiMAX Modem.
If your network has a small number of clients using peer to peer
applications, you can raise this number to ensure that their performance is
not degraded by the number of NAT sessions they can establish. If your
network has a large number of users using peer to peer applications, you
can lower this number to ensure no single client is using all of the available
NAT sessions.
Apply
Click to save your changes.
Cancel Click to return to the previous screen without saving your changes.
