ZyXEL Communications P-792H - Configuring a Generic Filter Rule

Chapter 32 Filter Configuration
P-792H v2 User’s Guide
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32.2.3 Configuring a Generic Filter Rule
This section shows you how to configure a generic filter rule. The purpose of
generic rules is to allow you to filter non-IP packets. For IP, it is generally easier to
use the IP rules directly.
For generic rules, the P-792H v2 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 P-792H v2 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 181 Menu 21.1.1.1: Generic Filter Rule
The following table describes the fields in the Generic Filter Rule menu.
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 Log= None
Action Matched= Check Next Rule
Action Not Matched= Check Next Rule
Table 129 Menu 21.1.1.1: Generic Filter Rule
FIELD DESCRIPTION
Filter # 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.
Filter
Type
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.
Active Select Yes to turn on the filter rule or No to turn it off.
Offset 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.
Length 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.