Chapter 19 Firewall
ZyWALL USG 1000 User’s Guide
284
Figure 186 Firewall
The following table describes the labels in this screen.
Table 88 Firewall
LABEL DESCRIPTION
Global Setting
Enable Firewall Select this check box to activate the firewall. The ZyWALL performs access control
when the firewall is activated.
Allow
Asymmetrical
Route
If an alternate gateway on the LAN has an IP address in the same subnet as the
ZyWALL’s LAN IP address, return traffic may not go through the ZyWALL. This is
called an asymmetrical or “triangle” route. This causes the ZyWALL to reset the
connection, as the connection has not been acknowledged.
Select this check box to have the ZyWALL 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 ZyWALL. A
better solution is to use virtual interfaces to put the ZyWALL
and the backup gateway on separate subnets. See Section
19.5 on page 282 for an example.