ZyXEL Communications ADSL2+ 4-port Gateway P-660H-D Series, User Manual

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P-660R-T Series User’s Guide
179 Chapter 22 Filter Configuration
Figure 115 Filter Rule Process
Start
Fetch First
Filter Set
Fetch First
Filter Rule
Active?
Execute
Filter Rule
Fetch Next
Filter Rule
Next filter
Rule
Available?
Fetch Next
Filter Set
Next Filter Set
Available?
Accept Packet Drop Packet
Yes
No
Yes
No
Yes
Packet
intoFilter
Filter Set
Forward
Drop
No
Check
Next
Rule
You can apply up to four filter sets to a particular port to block various types of packets.
Because each filter set can have up to six rules, you can have a maximum of 24 rules active for
a single port.
For incoming packets, your Prestige applies data filters only. Packets are processed depending
on whether a match is found. The following sections describe how to configure filter sets.
22.1.1 The Filter Structure of the Prestige
A filter set consists of one or more filter rules. Usually, you would group related rules, for
example, all the rules for NetBIOS, into a single set and give it a descriptive name. You can
configure up to twelve filter sets with six rules in each set, for a total of 72 filter rules in the
system.