Elian wants to detect illicit use of his servers. He is especially concerned about illicit use
by internal employees. Which of the following components should he install?

A.
A packet filtering firewall.

B.
A de-millitrization zone.

C.
A proxy server.

D.
Intrusion-detection system.

Explanation:
An intrusion-detection system will provide the monitoring capabilities
needed to detect possible illicit use of the system.
Incorrect Answers:
A: A packet filtering firewall will either allow or deny the passing of certain messagesthrough the
firewall. Capabilities of monitoring the origin and destination of the packetsare usually not
available, many packet filtering firewalls are actually routers withsupplicated filter tables. A firewall
is used to protect the internal network from theexternal network, so if the threat is an internal user,
the network is not protected from anattack from within the internal network.
B: A demilitarization zone (DMZ) is outside the internal network, and will not protect nordetect illicit
use of the internal network from internal attacks.
C: A proxy server stands between the internal and external networks, and will not protectnor
detect illicit use of the internal network from internal attacks.