ZyXEL Communications Prestige 1600 - Manual (Page 83)

Prestige 1600 Universal Access Concentrator
Filter Configuration 10-1
Chapter 10
Filter Configuration
This chapter shows you how to create and apply filter(s).
10.1 About Filtering
Your Prestige uses filters to decide whether 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 the 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 LAN 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 as shown in the
following figure.
Figure 10-1 Outgoing Packet Filtering Process
The following sections describe how to configure filter sets. Please see the application notes for more information
and examples on creating and configuring filters.
10.2 The Filter Structure of the Prestige
A filter set consists of one or more filter rules. Usually, you would group related rules, e.g., all the rules for
NetBIOS, into a single set and give it a descriptive name. The Prestige allows you to configure up to twelve filter
sets with six rules in each set, for a total of 72 filter rules in the system.
You can apply up to four filter sets to a particular port to block multiple types of packets. With each filter set
having up to six rules, you can have a maximum of 24 rules active for a single port.
The following diagram illustrates the logic flow when executing a filter rule.
Data
Filtering Outgoing
Packet
Drop
packet
Built-in
default
Call Filters
User-defined
Call Filters
(if applicable)
Initiate call
if line not up
Active Data
Send packet
and reset
Idle Timer
Or Or
Drop packet
if line not up Drop packet
if line not up
Send packet
but do not reset
Idle Timer
Send packet
but do not reset
Idle Timer
Match Match Match
No
match
No
match
No
match
Call Filtering