ZyXEL P-314Plus User Guide - Page 108

Prestige 314 PLUS Broadband Sharing Gateway with 4-Port Switch Outgoing Packet Data No match Match Call Filtering Built-in default Call Filters No match User-defined Call Filters (if applicable) Match Match No match Active Data Initiate call if line not up Send packet and reset Idle Timer Drop packet Drop packet if line not up Or Drop packet if line not up Or Send packet but do not reset Idle Timer Send packet but do not reset Idle Timer Figure 7-1 Outgoing Packet Filtering Process For incoming packets, your Prestige applies data filters only. Packets are processed depending upon whether a match is found. The following sections describe how to configure filter sets 7.1.1 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 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. Three sets of factory default filter rules have been configured in menu 21 to prevent NetBIOS traffic from triggering calls and to prevent incoming telnetting and FTP connections from the WAN side. A summary of their filter rules is shown in the figures that follow. The following diagram illustrates the logic flow when executing a filter rule. 7-2 Filter Configuration