User`s guide

Chapter 9 The NAT Configuration Screens
User’s Guide
97
9.4 Trigger Port
Some services use a dedicated range of ports on the client side and a dedicated range of ports
on the server side. With regular port forwarding you set a forwarding port in NAT to forward a
service (coming in from the server on the WAN) to the IP address of a computer on the client
side (LAN). The problem is that port forwarding only forwards a service to a single LAN IP
address. In order to use the same service on a different LAN computer, you have to manually
replace the LAN computer's IP address in the forwarding port with another LAN computer's IP
address,
Trigger port forwarding solves this problem by allowing computers on the LAN to
dynamically take turns using the service. The WiMAX Modem records the IP address of a
LAN computer that sends traffic to the WAN to request a service with a specific port number
and protocol (a "trigger" port). When the WiMAX Modem's WAN port receives a response
with a specific port number and protocol ("incoming" port), the WiMAX Modem forwards the
traffic to the LAN IP address of the computer that sent the request. After that computer’s
connection for that service closes, another computer on the LAN can use the service in the
same manner. This way you do not need to configure a new IP address each time you want a
different LAN computer to use the application.
Click ADVANCED > NAT Configuration > Trigger Port to maintain trigger port
forwarding rules for the WiMAX Modem.
Figure 54 ADVANCED > NAT Configuration > Trigger Port
Start Port
End Port
Enter the port number or range of port numbers you want to forward to the
specified server.
To forward one port number, enter the port number in the Start Port and End Port
fields.
To forward a range of ports,
• enter the port number at the beginning of the range in the Start Port field
• enter the port number at the end of the range in the End Port field.
Server IP Address
Enter the IP address of the server to which to forward packets for the selected port
number(s). This server is usually on the LAN.
Apply
Click to save your changes.
Cancel Click to return to the previous screen without saving your changes.
Table 36 ADVANCED > NAT Configuration > Port Forwarding > Rule Setup (continued)
LABEL DESCRIPTION