Wireless Cable Voice Gateway Model CVG824G Reference Manual
Port Triggering
Port Triggering is an advanced feature that allows you to dynamically open inbound ports based on outbound traffic on different ports. This feature can be used for gaming and other Internet applications.
Note: Port Forwarding is similar to port triggering, but it is static and has some limitations. Ports are open to traffic from the Internet until the port forwarding rule is removed. Additionally, port forwarding does not work well for some applications when your WAN IP address is assigned by DHCP, and is changed frequently. Port Triggering opens an incoming port temporarily and does not require the server on the internet to track your IP address if it is changed.
Port Triggering monitors outbound traffic. When the gateway detects traffic on the specified outbound port, it remembers the IP address of the computer that sent the data and “triggers” the incoming port. Incoming traffic on the triggered port is then forwarded to the triggering computer.
For example, port triggering can be used for Internet Relay Chat (IRC). When you connect to an IRC server, the server tries to connect back on the port to do an Ident lookup. Unless you have configured Port Forwarding to open that port, the traffic will be blocked. In this example, the initial login to the server in the range of ports is detected. This triggers the gateway to temporarily forward the port to the PC that initiated the login.
To configure Port Triggering
1.Under Advanced on the main menu, select Port Triggering The Port Triggering screen will display.
2.In the Trigger Range, enter the outbound ports that will be monitored for activity. This will be the “trigger.”
3.In the Target Range, enter the inbound ports that should be forwarded when the trigger occurs.
4.Select the appropriate protocol: TCP, UDP or Both.
5.Check the Enable box
6.Click Apply.
Protecting Your Network |
1.0, November 2006