19216811.liveDynamic DNS makes it much easier to access a server from the Internet because you can enter the
name in the web browser. Otherwise, you must know the IP address that the ISP assigned, which
typically changes.
How the Router Implements the Port Forwarding Rule
The following sequence shows the effects of a port forwarding rule:
1.
When you enter 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.
The router receives the message and finds your port forwarding rule for incoming port 80 traffic.
3.
The router changes the destination IP address in the message to 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 WiFi device that sent the web page request.
Manage Port Triggering for Services and Applications
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.
If you use applications such as multiplayer gaming, peer-to-peer connections, real-time
communications such as instant messaging, or remote assistance, enable Universal
Note
Plug and Play (UPnP). See
Improve Network Connections With Universal Plug and Play
on page 67.
Manage Port Forwarding and Port Triggering
226
Nighthawk AC1900 Smart WiFi Router Model R6900