User guide

Firewall Configuration
58 (98) EN/LZT 108 6492 R1
April 2003
Field Description
Attack Protection Select Enable to use the built-in firewall protections that
prevent the following common types of attacks:
IP Spoofing: Sending packets over the WAN interface using
an internal LAN IP address as the source address.
Tear Drop: Sending packets that contain overlapping
fragments.
Smurf and Fraggle: Sending packets that use the WAN or
LAN IP broadcast address as the source address.
Land Attack: Sending packets that use the same address as the
source and destination address.
Ping of Death: Illegal IP packet length.
DOS Protection Click the Enable radio button to use the following denial of
service protections:
SYN DoS, ICMP DoS and Per-host DoS protection.
Max Half open TCP Connection Sets the percentage of concurrent IP sessions that can be in the
half-open state. In ordinary TCP communication, packets are
in the half-open state only briefly as a connection is being
initiated; the state changes to active when packets are being
exchanged, or closed when the exchange is complete. TCP
connections in the half-open state can use up the available IP
sessions.
If the percentage is exceeded, then the half-open sessions will
be closed and replaced with new sessions as they are initiated.
Max ICMP Connection Sets the percentage of concurrent IP sessions that can be used
for ICMP messages.
If the percentage is exceeded, older ICMP IP sessions will be
replaced by new sessions as they are initiated.
Max Single Host Connection Sets the percentage of concurrent IP session that can originate
from a single computer. This percentage should take into
account the number of hosts on the LAN.
Log Destination Specifies how attempted violations of the firewall settings will
be tracked. Records of such events can be sent via Ethernet to
be handled by a system utility Ethernet to (Trace) or can be
e-mailed to specified administrators.