C
ONFIGURING
 
THE
 B
ARRICADE
4-28
Firewall
The Barricade’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. (See page 
4-46 for details.)
The firewall does not significantly affect system performance, so we advise 
leaving it enabled to protect your network.
Enable the firewall feature, and click Save Settings to proceed.