Which of the following refers to a security access control methodology whereby the 48-bit address is
assigned to each network card which is used to determine access to the network?

A.
Snooping

B.
Spoofing

C.
Encapsulation

D.
MAC filtering

Explanation:
In computer networking, MAC filtering (or EUI filtering, or layer 2 address filtering) refers to a
security access control methodology whereby the 48-bit address is assigned to each network card
which is used to determine access to the network. MAC addresses are uniquely assigned to each
card, so using MAC filtering on a network permits and denies network access to specific devices
through the use of blacklists and whitelists.

Answer A is incorrect. Snooping is an activity of observing the content that appears on a computer
monitor or watching what a user is typing. Snooping also occurs by using software programs to
remotely monitor activity on a computer or network device. Hackers or attackers use snooping
techniques and equipment such as keyloggers to monitor keystrokes, capture passwords and login
information, and to intercept e-mail and other private communications. Sometimes, organizations
also snoop their employees legitimately to monitor their use of organizations’ computers and track
Internet usage.

Answer B is incorrect. Spoofing is a technique that makes a transmission appear to have come from
an authentic source by forging the IP address, email address, caller ID, etc. In IP spoofing, a hacker
modifies packet headers by using someone else’s IP address to hide his identity. However, spoofing
cannot be used while surfing the Internet, chatting on-line, etc. because forging the source IP
address causes the responses to be misdirected.

Answer C is incorrect. The term encapsulation refers to the process where headers and trailers are
added around some data. A TCP/IP host sends data by performing a process in which four layers
encapsulate data (adds headers and trailers) before physically transmitting it.