User's Manual

Control Access to the Internet
30
U.S. Cellular® 4G LTE Router (LG2200D)
The following sequence shows the effects of the port forwarding rule you have defined:
1. The user of a remote computer opens a browser and requests a web page from
www.example.com, which resolves to the public IP address of your router. The remote
computer composes 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.
The remote computer then sends this request message through the Internet to your
router.
2. Your router receives the request message and looks in its rules table for any rules covering
the handling of incoming port 80 traffic. Your port forwarding rule specifies that incoming port
80 traffic should be forwarded to local IP address 192.168.0.123. Therefore, your router
modifies the destination information in the request message:
The destination address is replaced with 192.168.0.123.
Your router then sends this request message to your local network.
3. Your web server at 192.168.0.123 receives the request and composes a return message
with the requested web page data. Your web server then sends this reply message to your
router.
4. Your router performs Network Address Translation (NAT) on the source IP address, and
sends this request message through the Internet to the remote computer, which displays the
web page from www.example.com.
To configure port forwarding, you need to know which inbound ports the application needs.
You can usually find this information by contacting the publisher of the application or the
relevant user groups or news groups.
Set Up Port Forwarding to a Local Server
If you have a server in your home network, you can allow certain types of incoming traffic to
reach the server. For example, you might want to make a local web server, FTP server, or
game server visible and available to the Internet.
The router can forward incoming traffic with specific protocols to computers on your local
network. You can specify the servers for applications and you can also specify a default DMZ
server to which the router forwards all other incoming protocols.
¾ To forward specific incoming protocols:
1. Decide which type of service, application, or game you want to provide.
2. Find the local IP address of the computer on your network that will provide the service.
The server computer must always have the same IP address. To specify this setting, use
the reserved IP address feature. See Reserve LAN IP Addresses on page 82.