Chapter 2: WEB Configuration
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6. Port Triggers
Some Internet activities, such as interactive gaming, require that a PC on the WAN side of your gateway
be able to originate connections during the game with your game playing PC on the LAN side. You could
use the Advanced-Forwarding web page to construct a forwarding rule during the game, and then remove
it afterwards (to restore full protection to your LAN PC) to facilitate this. Port triggering is an elegant
mechanism that does this work for you, each time you play the game.
Fig. 22
Port Triggering works as follows. Imagine you want to play a particular game with PCs somewhere on the
Internet. You make one time effort to set up a Port Trigger for that game, by entering into
Trigger Range
the range of destination ports your game will be sending to, and entering into
Target Range
the range of
destination ports the other player (on the WAN side) will be sending to (ports your PC’s game receives
on). Application programs like games publish this information in user manuals. Later, each time you play
the game, the gateway automatically creates the forwarding rule necessary. This rule is valid until 10
minutes after it sees game activity stop. After 10 minutes, the rule becomes inactive until the next
matched outgoing traffic arrives.
For example, suppose you specify Trigger Range from 6660 to 6670 and Target Range from 113 to 113.
An outbound packet arrives at the gateway with your game-playing PC source IP address 192.168.0.10,
destination port 666 over TCP/IP. This destination port is within the Trigger destined for port 113 to your
game-playing PC at 192.168.0.10.
You can specify up to 10 port ranges on which to trigger.
Illustrations contained in this document are for representation only.
