ZyXEL nbg-334sh Manual Do Utilizador

 Chapter 11 Firewall

ZyXEL NBG-334SH User’s Guide

1 A computer on the LAN initiates a connection by sending a SYN packet to a receiving 

server on the WAN.

2 The ZyXEL Device reroutes the packet to Gateway A, which is in Subnet 2. 
3 The reply from the WAN goes to the ZyXEL Device. 
4 The ZyXEL Device then sends it to the computer on the LAN in Subnet 1.  

Figure 69   Using IP Alias to Solve the Triangle Route Problem

Click Security > Firewall to open the General screen. Use this screen to enable or disable the 
ZyXEL Device’s firewall, and set up firewall logs. 

Figure 70   General

The following table describes the labels in this screen.

Table 46   Firewall General

Enable 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.

Packet Direction

This is the direction of travel of packets.
Firewall rules are grouped based on the direction of travel of packets to which they 

apply.