Programmable Filtering
53
Pattern Filter Operators
The following operators are used in creating Pattern filters and will be discussed further in the following pages. For additional
information refer to the octet locations diagrams at the back of this manual. Each octet location may contain a HEX value.
-
offset
Used in pattern filters to determine the starting position to start the pattern checking.
Example:
12-80
This filter pattern will match if the packet information starting at
the 12
th
octet equals the 80 of the filter pattern.
|
OR
Used in combination filters when one
or
the other conditions must be met.
Example:
10-20|12-80
This filter pattern will match if the packet information starting at
the 10
th
octet equals the 20 of the filter pattern
or
if the packet
information starting at the 12
th
octet equals the 80 of the filter
pattern.
&
AND
Used in combination filters when one
and
the other conditions must be met.
Example:
10-20&12-80
This filter pattern will match if the packet information starting at
the 10
th
octet equals the 20 of the filter pattern
and
the packet
information starting at the 12
th
octet equals the 80 of the filter
pattern.
~
NOT
Used in pattern filters to indicate that all packets
not
matching the defined pattern will be filtered.
Example:
~12-80
This filter pattern will match if the packet information starting at
the 12
th
octet does not equal the 80 of the filter pattern.
( )
brackets
Used in pattern filters to separate portions of filter patterns for specific operators.
Example:
12-80&(14-24|14-32)
This filter pattern will be checked in two operations. First the
section in brackets will be checked and then the results of the first
check will be used in the second check using the first portion of
the filter patter. If the packet information starting at the 14
th
octet
equals 24 or 32, and the information at the 12
th
octet equals 80, the
filter pattern will match.
