User Manual

Specify Internet Port Settings
163
Nighthawk AC1750 Smart WiFi Router
1. When you type the URL www.example.com in your browser, the browser sends a web
page request message with the following destination information:
• Destination address. The IP address of www.example.com, which is the address of
your router.
• Destination port number. 80, which is the standard port number for a web server
process.
2. Your router receives the message and finds your port forwarding rule for incoming port 80
traffic.
3. The router changes the destination in the message to IP address 192.168.1.123 and sends
the message to that computer.
4. Your web server at IP address 192.168.1.123 receives the request and sends a reply
message to your router.
5. Your router performs Network Address Translation (NAT) on the source IP address, and
sends the reply through the Internet to the computer or wireless device that sent the web
page request.
Set Up Port Triggering
Port triggering is a dynamic extension of port forwarding that is useful in these cases:
• An application must use port forwarding to more than one local computer (but not
simultaneously).
• An application must open incoming ports that are different from the outgoing port.
With port triggering, the router monitors traffic to the Internet from an outbound “trigger” port
that you specify. For outbound traffic from that port, the router saves the IP address of the
computer that sent the traffic. The router temporarily opens the incoming port or ports that
you specify in your rule and forwards that incoming traffic to that destination.
Port forwarding creates a static mapping of a port number or range of ports to a single local
computer. Port triggering can dynamically open ports to any computer when needed and
close the ports when they are no longer needed.
Note: If you use applications such as multiplayer gaming, peer-to-peer
connections, real-time communications such as instant messaging, or
remote assistance (a feature in Windows XP), enable Universal Plug
and Play (UPnP). See
Improve Network Connections with Universal
Plug and Play on page 53.
Add a Port Triggering Service
 To add a port triggering service:
1. Launch an Internet browser from a computer or wireless device that is connected to the
network.