Implied Rules; Example Filter Set Page - Motorola 2200 Administrator's Handbook

Administrator's Handbook
Allow FTP access;
Deny FTP access;
Deny all other packets.
and a packet goes through these rules destined for FTP, the packet would forward through the first filter
rule (WWW), match the second rule (FTP), and the packet is allowed through. Even though the next rule is to
deny all FTP traffic, the FTP packet will never make it to this rule.

Implied rules

With a given set of filter rules, there is an Implied rule that may or may not be shown to the user. The
implied rule tells the filter set what to do with a packet that does not match any of the filter rules. An exam-
ple of implied rules is as follows:
Implied
Y+Y+Y=N
N+N+N=Y
Y+N+Y=N
Example filter set page
This is an example of the Motorola Netopia® filter set page:
160
Meaning
If all filter rules are YES, the implied rule is NO.
If all filter rules are NO, the implied rule is YES.
If a mix of YES and NO filters, the implied rule is NO.