Prestige 662H/HW Series User’s Guide

CHAPTER 36

Filter Configuration

This chapter shows you how to create and apply filters.

36.1 About 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 filter applications: data filtering and call filtering. Filters are subdivided into device and protocol filters, which are discussed later.

Data filtering screens data to determine if the packet should be allowed to pass. Data filters are divided into incoming and outgoing filters, depending on the direction of the packet relative to a port. Data filtering can be applied on either the WAN side or the Ethernet side. Call filtering is used to determine if a packet should be allowed to trigger a call.

Outgoing packets must undergo data filtering before they encounter call filtering. 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, for example, 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 shown next.

Figure 205 Outgoing Packet Filtering Process

Call Filtering

 

 

 

 

 

 

 

 

 

 

 

No

 

 

 

 

 

 

 

 

Active Data

 

 

 

 

 

Data

No

Built-in

 

match

User-defined

 

No

 

 

 

 

 

 

 

Outgoing

 

 

match

default

 

 

 

 

Call Filters

 

match

 

 

Initiate call

 

Packet

 

 

Filtering

 

 

 

 

 

 

 

 

 

if line not up

 

 

 

 

Call Filters

 

 

 

 

(if applicable)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Send packet

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and reset

 

 

 

 

Match

 

 

Match

 

 

 

 

 

Match

 

 

 

 

 

 

Idle Timer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Drop

 

Drop packet

 

 

 

 

 

Drop packet

 

 

 

 

 

 

 

 

 

 

 

 

 

packet

 

if line not up

 

 

 

 

 

if line not up

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Or

 

 

 

 

 

 

Or

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Send packet

 

 

 

 

 

Send packet

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

but do not reset

 

 

but do not reset

 

 

 

 

 

 

 

 

 

 

 

 

Idle Timer

 

 

 

 

 

 

Idle Timer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Two sets of factory 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 figure illustrates the logic flow when executing a filter rule.

Chapter 36 Filter Configuration

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