Figure 193 Menu 21.1.1.1: Generic Filter Rule; Table 117 Menu 21.1.1.1: Generic Filter Rule - ZyXEL Communications G.SHDSL.bis 4-port Security Gateway P-793H User Manual

For generic rules, the ZyXEL Device treats a packet as a byte stream as opposed to an IP or
IPX packet. You specify the portion of the packet to check with the Offset (from 0) and the
Length fields, both in bytes. The ZyXEL Device applies the Mask (bit-wise ANDing) to the
data portion before comparing the result against the Value to determine a match. The Mask
and Value are specified in hexadecimal numbers. Note that it takes two hexadecimal digits to
represent a byte, so if the length is 4, the value in either field will take 8 digits, for example,
FFFFFFFF.
To configure a generic rule, select Generic Filter Rule in the Filter Type field in menu
21.1.1.1 and press [ENTER] to open Generic Filter Rule, as shown below.

Figure 193 Menu 21.1.1.1: Generic Filter Rule

The following table describes the fields in the Generic Filter Rule menu.

Table 117 Menu 21.1.1.1: Generic Filter Rule

FIELD
Filter #
Filter Type
Active
Offset
Length
Mask
Value
More
Log
P-793H User's Guide
Menu 21.1.1.1 - Generic Filter Rule
Filter #: 1,1
Filter Type= Generic Filter Rule
Active= No
Offset= 0
Length= 0
Mask= N/A
Value= N/A
More= No
Action Matched= Check Next Rule
Action Not Matched= Check Next Rule
DESCRIPTION
This is the filter set, filter rule co-ordinates, in other words 2,3 refers to the second filter
set and the third rule of that set.
Use [SPACE BAR] and then [ENTER] to select a rule type. Parameters displayed below
each type will be different. TCP/IP filter rules are used to filter IP packets while generic
filter rules allow filtering of non-IP packets.
Options are Generic Filter Rule and TCP/IP Filter Rule.
Select Yes to turn on the filter rule or No to turn it off.
Enter the starting byte of the data portion in the packet that you wish to compare. The
range for this field is from 0 to 255.
Enter the byte count of the data portion in the packet that you wish to compare. The range
for this field is 0 to 8.
Enter the mask (in Hexadecimal notation) to apply to the data portion before comparison.
Enter the value (in Hexadecimal notation) to compare with the data portion.
If Yes, a matching packet is passed to the next filter rule before an action is taken; else
the packet is disposed of according to the action fields.
If More is Yes, then Action Matched and Action Not Matched will be No.
Select the logging option from the following:
None - No packets will be logged.
Action Matched - Only packets that match the rule parameters will be logged.
Action Not Matched - Only packets that do not match the rule parameters will be logged.
Both – All packets will be logged.
Chapter 30 Filter Configuration
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