Netgear DGND4000 User Manual download pdf (Page 79)

Security

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 defin

ed 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 auth

ors 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 ne

two

rk. This process is called service blocking or port filtering.

Note: This feature is for advanced administrators only. Incorrect

configuration can cause serious problems.

 To create firewall rules:

1. Select ADVANCED > Security > Firewall Rules to display th

e following screen:

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Netgear DGND4000 User Manual Page 79