Figure 102 Security > Firewall > Default Rule; Table 42 Security > Firewall > Default Rule - ZyXEL Communications NBG410W3G User Manual

Chapter 9 Firewall
Figure 102 SECURITY > FIREWALL > Default Rule
The following table describes the labels in this screen.
Table 42 SECURITY > FIREWALL > Default Rule
LABEL
0-100%
Enable Firewall
Allow
Asymmetrical
Route
174
DESCRIPTION
This bar displays the percentage of the ZyXEL Device's firewall rules storage space
that is currently in use. When the storage space is almost full, you should consider
deleting unnecessary firewall rules before adding more firewall rules.
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.
Note: When you activate the firewall, all current connections through
the ZyXEL Device are dropped when you apply your changes.
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
9.6.1 on page 173 for an example.
NBG410W3G Series User's Guide
Section