Block Access To Internet Services - NETGEAR DGND3300v2 User Manual

N300 Wireless Dual Band ADSL2+ Modem Router DGND3300v2

Block Access to Internet Services

The N300 wireless modem router allows you to block the use of certain Internet services by
computers on your network. This is called service blocking or port filtering. 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 your network sends a
request for service to a server computer on the Internet, 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 destination port number 80 is
an HTTP (Web server) request.
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To block access to Internet services:
1. From the main menu, select Security > Services. The Services screen displays.
2. To add a service, click Add Custom Service. The following screen displays.
3. Enter a name for the service.
4. From the Service Type drop-down list, select the application or service to be allowed or
blocked. If you know that the application uses either TCP or UDP, select the appropriate
protocol. If you are not sure, select Both.
5. You can block the specified service for a single computer, a range of computers with
consecutive IP addresses, or all computers on your network. Enter the starting port and
ending port numbers. If the application uses a single port number, enter that number in both
fields.
You need to determine which port number or range of numbers is used by the application.
The service port numbers for many common protocols are defined by the Internet
Engineering Task Force (IETF) and published in RFC1700, "Assigned Numbers." Service
numbers for other applications are typically chosen from the range 1024 to 65535 by the
authors of the application. You can often determine port number information by contacting
the publisher of the application, by asking user groups or newsgroups, or by searching.
6. Click Apply so that your changes take effect.
Security Settings
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