ZyXEL p-2802h-i1 Manual Do Utilizador

 Chapter 11 Firewalls

P-2802H(W)(L)-I Series User’s Guide

The following table describes the labels in this screen. 

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The ordering of your rules is very important as rules are applied in turn.

 for more information. 

Table 60   Firewall: General

Active Firewall

Select this check box to activate the firewall. The ZyXEL Device performs access 

control and protects against Denial of Service (DoS) attacks when the firewall is 

activated.

Bypass Triangle 

Route

If an alternate gateway on the LAN has an IP address in the same subnet as the 

ZyXEL Device’s LAN IP address, return traffic may not go through the ZyXEL 

Device. This is called an asymmetrical or “triangle” route. This causes the ZyXEL 

Device to reset the connection, as the connection has not been acknowledged.
Select this check box to have the ZyXEL Device permit the use of asymmetrical 

route topology on the network (not reset the connection). 

Note: Allowing asymmetrical routes may let traffic from the WAN go 

directly to the LAN without passing through the ZyXEL 
Device. A better solution is to use IP alias to put the ZyXEL 
Device and the backup gateway on separate subnets. See 

 for an example. 

Packet Direction

This is the direction of travel of packets (LAN to LAN / Router, LAN to WAN,  

WAN to WAN / Router, WAN to LAN).
Firewall rules are grouped based on the direction of travel of packets to which they 

apply. For example, LAN to LAN / Router means packets traveling from a 

computer/subnet on the LAN to either another computer/subnet on the LAN 

interface of the ZyXEL Device or the ZyXEL Device itself. 

Default Action

Use the drop-down list boxes to select the default action that the firewall is take on 

packets that are traveling in the selected direction and do not match any of the 

firewall rules. 
Select Drop to silently discard the packets without sending a TCP reset packet or 

an ICMP destination-unreachable message to the sender.
Select Reject to deny the packets and send a TCP reset packet (for a TCP packet) 

or an ICMP destination-unreachable message (for a UDP packet) to the sender.
Select Permit to allow the passage of the packets.

Log

Select the check box to create a log (when the above action is taken) for packets 

that are traveling in the selected direction and do not match any of your 

customized rules.

Expand...

Click this button to display more information.

Basic...

Click this button to display less information.

Apply

Click Apply to save your changes back to the ZyXEL Device.

Cancel

Click Cancel to begin configuring this screen afresh.