Which of the following is a process of monitoring data packets that travel across a network?

A.
Password guessing

B.
Packet sniffing

C.
Shielding

D.
Packet filtering

Explanation:
Packet sniffing is a process of monitoring data packets that travel across a network. The software
used for packet sniffing is known as sniffers. There are many packet-sniffing programs that are
available on the Internet. Some of these are unauthorized, which can be harmful for a network’s
security.
Answer option D is incorrect. Packet filtering is a method that allows or restricts the flow of specific
types of packets to provide security. It analyzes the incoming and outgoing packets and lets them
pass or stops them at a network interface based on the source and destination addresses, ports, or
protocols. Packet filtering provides a way to define precisely which type of IP traffic is allowed to
cross the firewall of an intranet. IP packet filtering is important when users from private intranets
connect to public networks, such as the Internet.
Answer option C is incorrect. Shielding is a way of preventing electronic emissions that are
generated from a computer or network from being used by unauthorized users for gathering
confidential information. It minimizes the chances of eavesdropping within a network. Shielding can
be provided by surrounding a computer room with a Farady cage. A Farady cage is a device that
prevents electromagnetic signal emissions from going outside the computer room. Shielding can also
protect wireless networks from denial of service (DoS) attacks.
Answer option A is incorrect. A password guessing attack occurs when an unauthorized user tries to
log on repeatedly to a computer or network by guessing usernames and passwords. Many password
guessing programs that attempt to break passwords are available on the Internet. Following are the
types of password guessing attacks:
Brute force attack

Dictionary attack
TechNet, Contents: “Data Security and Data Availability for End Systems”