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.
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
Note
XP), enable Universal Plug and Play (UPnP). See
Improve Network Connections With
Universal Plug and Play
on page 48.
Add a Port Triggering Service
To add a port triggering service:
1.
Launch a web browser from a computer or wireless device that is connected to the network.
2.
Type
.
A login window opens.
3.
Enter the router user name and password.
The user name is
admin
. The default password is
password
. The user name and password are
case-sensitive.
Specify Internet Port Settings
166