Netgear AC1900 Nighthawk™ Owner's Manual

Select ADVANCED > Advanced Setup > Port Forwarding/Port Triggering.

Select the Port Triggering radio button.

Clear the Disable Port Triggering check box.

If this check box is selected, the router does not use port triggering even if you have 
specified port triggering settings.

In the Port Triggering Timeout field, enter a value up to 9999 minutes. 

This value controls how long the inbound ports stay open when the router detects no 
activity. This value is required because the router cannot detect when the application 
terminates.

Some application servers, such as FTP and IRC servers, send replies to multiple port 
numbers. Using port triggering, you can tell the router to open more incoming ports when a 
particular outgoing port starts a session.

An example is Internet Relay Chat (IRC). Your computer connects to an IRC server at 

destination port 6667. The IRC server not only responds to your originating source port, but 
also sends an “identify” message to your computer on port 113. Using port triggering, you can 
tell the router, “When you initiate a session with destination port 6667, you must also allow 
incoming traffic on port 113 to reach the originating computer.” The following sequence shows 
the effects of the port triggering rule you have defined:

You open an IRC client program to start a chat session on your computer. 

Your IRC client composes a request message to an IRC server using a destination port 

number of 6667, the standard port number for an IRC server process. Your computer then 

sends this request message to your router.

Your router creates an entry in its internal session table describing this communication 

session between your computer and the IRC server. Your router stores the original 

information, performs Network Address Translation (NAT) on the source address and port, 

and sends this request message through the Internet to the IRC server. 

Noting your port triggering rule and observing the destination port number of 6667, your 

router creates another session entry to send any incoming port 113 traffic to your computer.