ZyXEL Communications P-793H User Manual
Chapter 30 Filter Configuration
P-793H User’s Guide
296
30.1.1 The Filter Structure of the ZyXEL Device
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. The ZyXEL
Device 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 cannot mix device filter rules and protocol filter rules within
the same set. 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.
Sets of factory default filter rules have been configured in menu 21 to prevent NetBIOS traffic
from triggering calls and to prevent incoming telnet sessions. 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. See also
example all the rules for NetBIOS, into a single set and give it a descriptive name. The ZyXEL
Device 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 cannot mix device filter rules and protocol filter rules within
the same set. 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.
Sets of factory default filter rules have been configured in menu 21 to prevent NetBIOS traffic
from triggering calls and to prevent incoming telnet sessions. 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. See also
for the logic flow when executing an IP filter.