Which of the following devices is BEST suited to protect an HTTP-based application that is susceptible to
injection attacks?

A.
Protocol filter

B.
Load balancer

C.
NIDS

D.
Layer 7 firewall

Explanation:
An application-level gateway firewall filters traffic based on user access, group membership, the
application or service used, or even the type of resources being transmitted. This type of firewall operates
at the Application layer (Layer 7) of the OSI model.Incorrect Answers:
A: The Protocol Filter feature is used to block unwanted traffic from your network. The feature is
commonly used to make sure employees, students or end users are using their Internet access for its
intended productive use.
B: A load balancer is used to distribute network traffic load across a number of network links or network
devices.
C: A network-based IDS (NIDS) watches network traffic in real time, and is reliable for detecting networkfocused attacks, such as bandwidth-based DoS attacks.

Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 6, 10, 82
http://www.clearcenter.com/support/documentation/clearos_enterprise_5.1/user_guide/protocol_filter