Port Triggers - Technicolor TC7200.20 User Manual

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.2-23 Gateway\Advanced\Port Triggers
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 Start
Port and Tigger End Port the range of destination ports your game will be sending to, and entering into
Target Start Port 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.
e.g., 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.
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