Firewall Rules - NETGEAR DGND4000 User Manual

N750 Wireless Dual Band Gigabit ADSL Modem Router DGND4000

Firewall Rules

Services are functions performed by server computers at the request of client computers. For
example, web servers serve web pages, time servers serve time and date information, and
game hosts serve data about other players' moves. When a computer on the Internet sends
a request for service to a server computer, the requested service is identified by a service or
port number. This number appears as the destination port number in the transmitted IP
packets. For example, a packet that is sent with the destination port number 80 is an HTTP
(web server) request.
The service numbers for many common protocols are defined by the Internet Engineering
Task Force (IETF at http://www.ietf.org/) and published in RFC1700, "Assigned Numbers."
Service numbers for other applications are typically chosen from the range 1024–65535 by
the authors of the application. Although the wireless modem router already holds a list of
many service port numbers, you are not limited to these choices. You can often determine
port number information by contacting the publisher of the application, by asking user groups
or newsgroups, or by searching.
The Firewall Rules screen lets you block or allow specific Internet traffic services by
computers on your network. This process is called service blocking or port filtering.
Note: This feature is for advanced administrators only. Incorrect
configuration can cause serious problems.
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To create firewall rules:
1. Select ADVANCED > Security > Firewall Rules to display the following screen:
Security
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