Prestige 650M-17 ADSL Modem
Filter Set Configuration
5-1
Chapter 5
Filter Set Configuration
This chapter shows you how to create and apply filters.
5.1 About
Filtering
Your Prestige uses filters to decide whether or not to allow passage of data packets. Data filtering examines
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 Ethernet side.
Outgoing packets 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 illustrated in the figure shown next.
Figure 5-1 Outgoing Packet Filtering Process
The following figure 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
