Table of Contents
Advertisement
Chapter 12 Firewalls
The following table describes the labels in this screen.
Table 43 Security > Firewall > General
LABEL
Active Firewall
Bypass Triangle
Route
Packet
Direction
Default Action
Log
Expand...
Basic...
Apply
Cancel
144
DESCRIPTION
Select this check box to activate the firewall. The IAD 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 IAD's LAN IP address, return traffic may not go through
the IAD. This is called an asymmetrical or "triangle" route. This causes
the IAD to reset the connection, as the connection has not been
acknowledged.
Select this check box to have the IAD 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 IAD. A better
solution is to use IP alias to put the IAD and the backup
gateway on separate subnets. See
155
for an example.
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 IAD or the IAD 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 button to display more information.
Click this button to display less information.
Click Apply to save your changes back to the IAD.
Click Cancel to begin configuring this screen afresh.
Section 12.5.3.1 on page
IAD User's Guide
Advertisement
Table of Contents
