User's Manual

F IREWALL
4-49
Firewall
The Barricade Router’s firewall inspects packets at the application layer,
maintains TCP and UDP session information including time-outs and the
number of active sessions, and provides the ability to detect and prevent
certain types of network attacks.
Network attacks that deny access to a network device are called
Denial-of-Service (DoS) attacks. DoS attacks are aimed at devices and
networks with a connection to the Internet. Their goal is not to steal
information, but to disable a device or network so users no longer have
access to network resources.
The Barricade protects against the following DoS attacks: IP Spoofing,
Land Attack, Ping of Death, IP with zero length, Smurf Attack, UDP port
loopback, Snork Attack, TCP null scan, and TCP SYN flooding.
(For details see“Intrusion Detection,” page 4-56.)
The firewall does not significantly affect system performance, so we advise
enabling the function to protect your network.
Select Enable and click the SAVE SETTINGS button.