User manual

8-10 Packet Filter
s
Generic Filter Rules
Protocol-independent generic filter rules are similar in format to
protocol filter rules. The following table shows the
The rule syntax is:
<line #> <verb> <keyword> <operator> origin=<DATA | FRAME>
offset=<value>/length=<value>/mask=<hexadecimal value>/
value=<hexadecimal value>
The following table describes each field used in the rule syntax:
Field Description
line #
Each rule must have a unique line number (1-999).
You must arrange rules in increasing order.
verb
This field can be one of the following:
ACCEPT - allow the packet access if the
condition is met
REJECT - do not allow the packet access if the
condition is met
AND - logically use the AND condition with
condition of the next rule to determine if the
packet is accepted or rejected. Both defined
conditions must be met.
keyword
The keywords for a generic filter rule is always
GENERIC.
operator
The operator for a generic filter rule is always: =>
origin
Can be either FRAME or DATA
offset
Number of bytes offset from the origin.
length
number of bytes to compare and mask.
mask
bit mask in hexidecimal format for logical and
packet content.
value
The value in hexidecimal format used to compare
with the masked packet contents
For example, a generic filter rule might look like this:
010 ACCEPT generic => origin=data/offset=22/length=6/
mask=0xFFFFFFFFFFFF/value=0x0800096f39c8;