ZyXEL Communications G-2000 Plus - Manual (Page 321)

ZyAIR G-2000 Plus User’s Guide
Chapter 29 Filter Configuration 320
For generic rules, the ZyAIR 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 ZyAIR 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
21.1.4.1 and press [ENTER] to open Generic Filter Rule, as shown below.
Figure 174 Menu 21.1.4.1 Generic Filter Rule
Menu 21.1.4.1 - Generic Filter Rule
Filter #: 4,1
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
Press ENTER to Confirm or ESC to Cancel:
Press Space Bar to Toggle.
The following table describes the fields in the Generic Filter Rule menu.
Table 109 Generic Filter Rule Menu Fields
FIELD DESCRIPTION OPTIONS
Filter # This is the filter set, filter rule co-ordinates, i.e., 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.
Generic Filter
Rule
TCP/IP Filter
Rule
Active Select Yes to turn on the filter rule or No to turn it off. Yes / No
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.
0-255
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.
0-8
Mask Enter the mask (in Hexadecimal notation) to apply to the data
portion before comparison.
Value Enter the value (in Hexadecimal notation) to compare with the data
portion.