ZyXEL Communications NXC5200 User Manual page 258

Hide thumbs Also See for NXC5200:

Table of Contents

Chapter 18 Firewall

• The NXC applies NAT (Destination NAT) settings before applying the firewall

rules. So for example, if you configure a NAT entry that sends WAN traffic to a

LAN IP address, when you configure a corresponding firewall rule to allow the

traffic, you need to set the LAN IP address as the destination.

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

Figure 113 Configuration > Firewall

The following table describes the labels in this screen.

Table 92 Configuration > Firewall

Asymmetrical

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

control when the firewall is activated.

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

as the NXC's LAN IP address, return traffic may not go through the NXC.

This is called an asymmetrical or "triangle" route. This causes the NXC to

reset the connection, as the connection has not been acknowledged.

Select this check box to have the NXC 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 NXC. A better

solution is to use virtual interfaces to put the NXC and the

backup gateway on separate subnets.

NXC5200 User's Guide

Troubleshooting

Nxc5200 - v2.20