ZyXEL Communications Corporation P873HNUP51B Manuel D’Utilisation
Chapter 11 Network Address Translation (NAT)
P-873HNUP-51B User’s Guide
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11.3.1 Add New Application
This screen lets you create new NAT application rules. Click Add new application in the
Applications screen to open the following screen.
Applications screen to open the following screen.
Figure 63 Applications: Add
The following table describes the labels in this screen.
11.4 The Port Triggering Screen
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.
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 ZyXEL Device 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 ZyXEL Device's WAN port receives a response with a specific port number and protocol
("open" port), the ZyXEL Device 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
turns using the service. The ZyXEL Device 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 ZyXEL Device's WAN port receives a response with a specific port number and protocol
("open" port), the ZyXEL Device 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
Table 46 Applications: Add
LABEL
DESCRIPTION
WAN Interface
Select the WAN interface that you want to apply this NAT rule to.
Server IP
Address
Address
Enter the inside IP address of the application here.
Application
Category
Category
Select the category of the application from the drop-down list box.
Application
Forwarded
Forwarded
Select a service from the drop-down list box and the ZyXEL Device automatically
configures the protocol, start, end, and map port number that define the service.
configures the protocol, start, end, and map port number that define the service.
View Rule
Click this to display the configuration of the service that you have chosen in
Application Fowarded.
Application Fowarded.
Apply
Click Apply to save your changes.
Cancel
Click Cancel to exit this screen without saving.