Port Forwarding - NETGEAR CG3000D-1CXNAS User Manual

Port Forwarding

A firewall has default rules for inbound traffic (WAN to LAN) and for outbound traffic. Port
forwarding affects the inbound rules. These rules restrict access from outsiders. By default,
the gateway blocks access from outside except responses to requests from the LAN side.
You can use port forwarding to add rules to specify exceptions to the default rule.
Because the gateway uses Network Address Translation (NAT), your network presents only
one IP address to the Internet, and outside users cannot directly address any of your local
computers. However, by defining an inbound rule you can make a local server (for example, a
web server or game server) or computer visible and available to the Internet. The rule tells
the Gateway to direct inbound traffic for a particular service to one local server or computer
based on the destination port number. This is also known as port forwarding.
Some residential broadband ISPs do not allow you to run server processes (such as a Web
or ftp server) from your location. Your ISP might check for servers and suspend your account
if it finds active services at your location. See your ISP's Acceptable Use policy.
To configure port forwarding and services for specific inbound traffic:
In the main menu, under Advanced, select Port Forwarding.
1.
In the Service field, select a service from the
2.
drop-down list. (For example, FTP, which uses
TCP ports 20 and 21.)
To add a custom rule that is not in the list of
3.
services, specify these settings in the Add
Custom Rules table:
Name. Enter a name for the service.
•
Start Port. Enter the start port for the
•
service.
End Port.Enter the end port for the
•
service.
Protocol. Select the protocol for the ports:
•
TCP. Select TCP only.
-
UDP. Select UDP only.
-
Both. Select both TCP and UDP.
-
Local IP Address. Complete the local IP address for the computer that is using the
•
service.
Perform one of these actions:
4.
Click Add. The Active Forwarding Rules table displays the list of forwarded ports.
•
To delete a service, select the radio button in the Active Forwarding Rules table for the
•
service that you want to delete, and then click Delete.
To reset the selection in the Services field and to clear all the fields in the Add
•
Custom Rules table, click Reset.
30 | Chapter 4: Advanced Settings
Wireless Cable Gateway CG3000D-1CXNAS