C
ONFIGURING
THE
B
ARRICADE
4-40
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. (See page
4-46 for details.)
The firewall does not significantly affect system performance, so we advise
leaving it enabled to protect your network. Select Enable and click the
“APPLY” button to open the Firewall submenus.