Cisco DPC User Manual page 53

How Do I Configure My DOCSIS Residential Gateway?
Configuring TCP/UDP Port Triggers
Use the Setup Advanced Settings - Port Triggers page to configure TCP/UDP port
triggers. Port triggering is similar to port forwarding but is dynamic. In other words,
the system does not hold the ports open indefinitely. For example, when the
residential gateway detects outgoing data on a specific IP port number set in the
"Trigger Range," the resulting ports set in the "Target Range" will open for
incoming data. If the system detects no outgoing traffic on the "Trigger Range" ports
for a period of 10 minutes, the "Target Range" ports close. This is a safer method for
opening specific ports for special applications, such as, video conferencing
programs, interactive gaming, and file transfer in chat programs. This is safe because
the ports are dynamically triggered and not held open continuously or left open
erroneously by the router administrator. Therefore, these ports are not exposed and
vulnerable for potential hackers to discover.
Note: If you are not familiar with the advanced settings detailed in this section,
contact your service provider before you attempt to change any of the residential
gateway default advanced port triggers settings.
Click Port Triggers in the Advanced Settings section of the Setup page to access the
Setup Advanced Settings - Port Triggers page.
Setup Advanced Settings - Port Triggers Page
The following illustration is an example of the Setup Advanced Settings - Port
Triggers page.
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