ZyXEL Communications NBG420N - Manual (Page 155)

Chapter 13 Firewall
NBG420N User’s Guide
155
1 A computer on the LAN initiates a connection by sending a SYN packet to a receiving
server on the WAN.
2 The NBG420N reroutes the packet to Gateway A, which is in Subnet 2.
3 The reply from the WAN goes to the NBG420N.
4 The NBG420N then sends it to the computer on the LAN in Subnet 1.
Figure 96 Using IP Alias to Solve the Triangle Route Problem
13.3 General Firewall Screen
Click Security > Firewall to open the General screen. Use this screen to enable or disable the
NBG420N’s firewall, and set up firewall logs.
Figure 97 Security > Firewall > General l
The following table describes the labels in this screen.
Table 57 Security > Firewall > General
LABEL DESCRIPTION
Enable Firewall Select this check box to activate the firewall. The NBG420N 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.