Chapter 34 Filter Configuration; About Filtering - ZyXEL Communications Prestige 652H series User Manual

Prestige 652H/HW Series User's Guide
Chapter 34
Filter Configuration
This chapter shows you how to create and apply filters.

34.1 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.
Filter Configuration 34-1