Netgear DG834G DG834G Original Reference Manual - Page 71

Order of Precedence for Rules, Services

Page 71 highlights

Reference Manual for the 54 Mbps Wireless ADSL Firewall Router DG834G Order of Precedence for Rules As you define new rules, they are added to the tables in the Rules menu, as shown in Figure 5-8: Figure 5-8: Rules table with examples For any traffic attempting to pass through the firewall, the packet information is subjected to the rules in the order shown in the Rules Table, beginning at the top and proceeding to the default rules at the bottom. In some cases, the order of precedence of two or more rules may be important in determining the disposition of a packet. The Move button allows you to relocate a defined rule to a new position in the table. Services 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 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) 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. Protecting Your Network 5-11

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Reference Manual for the 54 Mbps Wireless ADSL Firewall Router DG834G
Protecting Your Network
5-11
Order of Precedence for Rules
As you define new rules, they are added to the tables in the Rules menu, as shown in
Figure 5-8
:
Figure 5-8:
Rules table with examples
For any traffic attempting to pass through the firewall, the packet information is subjected to the
rules in the order shown in the Rules Table, beginning at the top and proceeding to the default rules
at the bottom. In some cases, the order of precedence of two or more rules may be important in
determining the disposition of a packet. The Move button allows you to relocate a defined rule to a
new position in the table.
Services
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 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) 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.