ZyXEL Communications P-2612HW Series User Manual page 235

The following table describes the labels in this screen.
Table 72 Security > Firewall > General
LABEL
Active Firewall
Bypass Triangle
Route
Packet
Direction
Default Action
Log
Expand...
Basic...
Apply
Cancel
P-2612HW Series User's Guide
DESCRIPTION
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.
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
Section 12.5.4.1 on page 247
This is the direction of travel of packets (LAN to LAN / Router, LAN to
WAN, WAN to WAN / Router, WAN to LAN).
Firewall rules are grouped based on the direction of travel of packets to
which they apply. For example, LAN to LAN / Router means packets
traveling from a computer/subnet on the LAN to either another
computer/subnet on the LAN interface of the ZyXEL Device or the ZyXEL
Device itself.
Use the drop-down list boxes to select the default action that the
firewall is to take on packets that are traveling in the selected direction
and do not match any of the firewall rules.
Select Drop to silently discard the packets without sending a TCP reset
packet or an ICMP destination-unreachable message to the sender.
Select Reject to deny the packets and send a TCP reset packet (for a
TCP packet) or an ICMP destination-unreachable message (for a UDP
packet) to the sender.
Select Permit to allow the passage of the packets.
Select the check box to create a log (when the above action is taken)
for packets that are traveling in the selected direction and do not match
any of your customized rules.
Click this to display more information.
Click this to display less information.
Click this to save your changes.
Click this to restore your previously saved settings.
Chapter 12 Firewall
for an example.
235