ZyAIR Wireless Gateway Series User’s Guide

Table 24-4 Menu 21.1.4.1 Generic Filter Rule

FIELD

DESCRIPTION

EXAMPLE

 

 

 

Offset

Type the starting byte of the data portion in the packet that you want to

0

 

compare. The range for this field is from 0 to 255.

(default)

 

 

 

Length

Type the byte count of the data portion in the packet that you want to

0

 

compare. The range for this field is 0 to 8.

(default)

 

 

 

Mask

Type the mask (in Hexadecimal) to apply to the data portion before

 

 

comparison.

 

Value

Type the value (in Hexadecimal) to compare with the data portion.

 

 

 

 

More

If Yes, a matching packet is passed to the next filter rule before an action

No

 

is taken or else the packet is disposed of according to the action fields.

(default)

 

If More is Yes, then Action Matched and Action Not Matched will be

 

 

N/A.

 

Log

Select the logging option from the following:

 

 

None – No packets will be logged.

None

 

Action Matched – Only matching packets and rules will be logged.

 

 

Action Not Matched – Only packets that do not match the rule

 

 

parameters will be logged.

 

 

Both – All packets will be logged.

 

Action

Select the action for a matching packet. Choices are Check Next Rule,

Check Next

Matched

Forward or Drop.

Rule

Action Not

Select the action for a packet not matching the rule. Choices are Check

Check Next

Matched

Next Rule, Forward or Drop.

Rule

When you have completed this menu, press [ENTER] at the prompt “Press ENTER to confirm or ESC to cancel” to save your configuration or press [ESC] to cancel and go back to the previous screen.

24.4 Filter Types and NAT

There are two classes of filter rules, Generic Filter Device rules and Protocol Filter (TCP/IP) rules. Generic Filter rules act on the raw data from/to LAN and WAN. Protocol Filter rules act on IP packets.

When NAT (Network Address Translation) is enabled, the inside IP address and port number are replaced on a connection-by-connection basis, which makes it impossible to know the exact address and port on the wire. Therefore, the ZyAIR applies the protocol filters to the “native” IP address and port number before NAT for outgoing packets and after NAT for incoming packets. On the other hand, the generic (or device) filters are applied to the raw packets that appear on the wire. They are applied at the point where the ZyAIR

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Filter and Firewall Configuration