ZyAIR G-2000 Plus User’s Guide

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= NoLog= 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.

Generic Filter

 

Parameters displayed below each type will be different. TCP/IP filter

Rule

 

rules are used to filter IP packets while generic filter rules allow

TCP/IP Filter

 

filtering of non-IP packets.

 

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

0-255

 

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

0-8

 

to compare. The range for this field is 0 to 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.

 

Chapter 29 Filter Configuration

320