Reference Guide for the Model RT328 and Model RH348 ISDN Routers

For incoming packets, the router applies data filters only. Packets are processed depending on whether a match is made. The router allows you to customize the filter sets that you want to use. The following sections describe how to configure the filter sets for the router.

Router Filter Structure

You can configure up to 12 filter sets, each with up to six rules. For IP packets, these rules involve comparing the protocol type of a data packet (for example, TCP, UDP), source or destination addresses, or port numbers. Also, a generic filter may be defined to merely test for a byte or pattern

of bytes in a particular location in the packet. When a rule is met (or not met), a user-specified action is taken. This action may be to forward the packet, drop the packet, or go to the next rule.

When implementing these filter sets, you can link up to four of the filter sets together to screen the data packet. Therefore, with each filter set having up to six rules, you can have a maximum of 24 rules active for a single filtering application.

Configuring a Filter Set

To configure a filter set, select option 21 in the Main Menu. This selection brings up Menu 21 - Filter Set Configuration. From this menu, you can choose from among 12 filter sets. Select the filter that you want to configure or choose an unused set to create a new filter. In order to distinguish between the 12 filter sets, each filter set should have a name or some comments. When you select a set for editing, you will be prompted to provide some descriptive text to be displayed in the comment field of Menu 21 next to the filter number.

When you have finished filling in the Edit Comments field, press [Enter] at the Press ENTER to

Confirm... prompt to confirm your selections, or press [Esc] at any time to cancel your selections.

The new information will now be displayed in the read-only section of Menu 21 - Filter Set

Configuration.

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Filter Configuration