ZyXEL Communications P-792H - Page 123

Chapter 9 Firewalls
P-792H v2 User’s Guide
123
The following table describes the labels in this screen.
Table 31 Security > Firewall > General
LABEL DESCRIPTION
Active Firewall Select this check box to activate the firewall. The P-792H v2 performs
access control and protects against Denial of Service (DoS) attacks
when the firewall is activated.
Bypass Triangle
Route
If an alternate gateway on the LAN has an IP address in the same
subnet as the P-792H v2’s LAN IP address, return traffic may not go
through the P-792H v2. This is called an asymmetrical or “triangle”
route. This causes the P-792H v2 to reset the connection, as the
connection has not been acknowledged.
Select this check box to have the P-792H v2 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 P-792H v2. A
better solution is to use IP alias to put the P-792H v2 and the
backup gateway on separate subnets. See Section 9.5.4.1
on page 136 for an example.
Packet
Direction
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 P-792H v2 or the P-792H
v2 itself.
Default Action 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.
Log 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.
Expand... Click this to display more information.
Basic... Click this to display less information.
Apply Click this to save your changes.
Cancel Click this to restore your previously saved settings.