ZyXEL Communications 1001H manual Filter Configuration, About Filtering

P100IH ISDN Router

Chapter 9:

Filter Configuration

9.1About Filtering

Your Prestige uses filters to decide whether or not to allow passage of a data packet and/or to make a call. There are two types of filters: data filters and call filters.

Data filters screen the data to determine if the packet should be allowed to pass. Data filters are further divided into incoming and outgoing filters, depending on the direction of the packet relative to a port. Call filters are used to determine if a packet should be allowed to trigger a call.

Outgoing packets must pass through the data filters before they encounter the call filters. Call filters are divided into two groups, the built-in call filters and user-defined call filters. Your Prestige has built-in call filters that prevent administrative, e.g., RIP packets from triggering calls. These filters are always enabled and not accessible to you. Your Prestige applies the built-in filters first and then the user-defined call filters, if applicable, as illustrated in Figure 9-2 Outgoing Packet Filtering Process.

Two sets of factory default filter rules have been configured in Menu 21 to prevent NetBIOS traffic from triggering calls. A summary of their filter rules is shown in the figures that follow.

The following diagram illustrates the logic flow when executing a filter rule.

Filter Configuration 9-1