ZyXEL NBG-318S Guia Do Utilizador

 Chapter 12 Firewall

NBG-318S 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 NBG-318S reroutes the packet to Gateway A, which is in Subnet 2. 
3 The reply from the WAN goes to the NBG-318S. 
4 The NBG-318S then sends it to the computer on the LAN in Subnet 1. 

Figure 70   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 
NBG-318S’s firewall, and set up firewall logs. 

Figure 71   Security > Firewall > General l

The following table describes the labels in this screen.

Table 49   Security > Firewall > General 

Enable Firewall

Select this check box to activate the firewall. The NBG-318S 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.