CompTIA Security+ Question H-80

Which device monitors network traffic in a passive manner?

A. Sniffer
B. IDS
C. Firewall
D. Web browser

Answer: A

Explanation:
A sniffer is another name for a protocol analyzer. A protocol analyzer performs its function in a passive manner. In other words, computers on the network do not know that their data packets have been captured. A Protocol Analyzer is a hardware device or more commonly a software program used to capture network data communications sent between devices on a network. Capturing packets sent from a computer system is known as packet sniffing. Well known software protocol analyzers include Message Analyzer (formerly Network Monitor) from Microsoft and Wireshark (formerly Ethereal).

A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn’t generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. The NIC is put into promiscuous mode, and it reads communications between computers within a particular segment. This allows the sniffer to seize everything that is flowing in the network, which can lead to the unauthorized access of sensitive data. A packet sniffer can take the form of either a hardware or software solution. A sniffer is also known as a packet analyzer.

CompTIA Security+ Question F-27

Which statement is TRUE about the operation of a packet sniffer?

A. It can only have one interface on a management network.
B. They are required for firewall operation and stateful inspection.
C. The Ethernet card must be placed in promiscuous mode.
D. It must be placed on a single virtual LAN interface.

Answer: C

Explanation:
A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn’t generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. The NIC is put into promiscuous mode, and it reads communications between computers within a particular segment. This allows the sniffer to seize everything that is flowing in the network, which can lead to the unauthorized access of sensitive data. A packet sniffer can take the form of either a hardware or software solution. A sniffer is also known as a packet analyzer.

CompTIA Security+ Question E-15

Which of the following network devices is used to analyze traffic between various network interfaces?

A. Proxies
B. Firewalls
C. Content inspection
D. Sniffers

Answer: D

Explanation:
A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn’t generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. The NIC is put into promiscuous mode, and it reads communications between computers within a particular segment. This allows the sniffer to seize everything that is flowing in the network, which can lead to the unauthorized access of sensitive data. A packet sniffer can take the form of either a hardware or software solution. A sniffer is also known as a packet analyzer.

CompTIA Security+ Question D-91

Which of the following wireless security measures can an attacker defeat by spoofing certain properties of their network interface card?

A. WEP
B. MAC filtering
C. Disabled SSID broadcast
D. TKIP

Answer: B

Explanation:
MAC filtering is typically used in wireless networks. In computer networking, MAC Filtering (or GUI filtering, or layer 2 address filtering) refers to a security access control method whereby the 48-bit address assigned to each network card 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. While the restriction of network access through the use of lists is straightforward, an individual person is not identified by a MAC address, rather a device only, so an authorized person will need to have a whitelist entry for each device that he or she would use to access the network. While giving a wireless network some additional protection, MAC filtering can be circumvented by scanning a valid MAC (via airodumping) and then spoofing one’s own MAC into a validated one.

CompTIA Security+ Question B-31

Which of the following software allows a network administrator to inspect the protocol header in order to troubleshoot network issues?

A. URL filter
B. Spam filter
C. Packet sniffer
D. Switch

Answer: C

Explanation:
Every data packet transmitted across a network has a protocol header. To view a protocol header, you need to capture and view the contents of the packet with a packet sniffer.

A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn’t generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. The NIC is put into promiscuous mode, and it reads communications between computers within a particular segment. This allows the sniffer to seize everything that is flowing in the network, which can lead to the unauthorized access of sensitive data. A packet sniffer can take the form of either a hardware or software solution. A sniffer is also known as a packet analyzer.

CompTIA Security+ Question B-7

Maintenance workers find an active network switch hidden above a dropped-ceiling tile in the CEO’s office with various connected cables from the office. Which of the following describes the type of attack that was occurring?

A. Spear phishing
B. Packet sniffing
C. Impersonation
D. MAC flooding

Answer: B

Explanation:
A Protocol Analyzer is a hardware device or more commonly a software program used to capture network data communications sent between devices on a network. Capturing packets sent from a computer system is known as packet sniffing. However, packet sniffing requires a physical connection to the network. The switch hidden in the ceiling is used to provide the physical connection to the network. Well known software protocol analyzers include Message Analyzer (formerly Network Monitor) from Microsoft and Wireshark (formerly Ethereal).

A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn’t generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. The NIC is put into promiscuous mode, and it reads communications between computers within a particular segment. This allows the sniffer to seize everything that is flowing in the network, which can lead to the unauthorized access of sensitive data. A packet sniffer can take the form of either a hardware or software solution. A sniffer is also known as a packet analyzer.

CompTIA Network+ Question C-68

A technician needs to set aside addresses in a DHCP pool so that certain servers always receive the same address. Which of the following should be configured?

A. Leases
B. Helper addresses
C. Scopes
D. Reservations

Correct Answer: D

Explanation:
A reservation is used in DHCP to ensure that a computer always receives the same IP address. To create a reservation, you need to know the hardware MAC address of the network interface card that should receive the IP address.
For example, if Server1 has MAC address of 00:A1:FB:12:45:4C and that computer should always get 192.168.0.7 as its IP address, you can map the MAC address of Server1 with the IP address to configure reservation.

CompTIA Network+ Question B-60

A network technician has just configured NAC for connections using Cat 6 cables. However, none of the Windows clients can connect to the network. Which of the following components should the technician check on the Windows workstations? (Choose two.)

A. Start the Wired AutoConfig service in the Services console
B. Enable IEEE 802.1q Authentication in Network Interface Card Properties
C. Enable IEEE 802.1x Authentication in Network Interface Card Properties
D. Start the Wireless AutoConfig service in the Services console
E. Enable IEEE 802.3 Ethernet IPv6 in Network Interface Card Properties

Correct Answer: AC

CompTIA Network+ Question B-1

A network administrator is using a packet analyzer to determine an issue on the local LAN. Two separate computers are showing an error message on the screen and are unable to communicate with other computers in the same lab. The network administrator looks at the following output:

SRC MAC SRC IP DST MAC DST IP
00:1D:1F:AB:10:7D192.168.1.10:200015:BE:9F:AB:10:1D192.168.1.14:1200
05:DD:1F:AB:10:27192.168.1.10:100022:C7:2F:AB:10:A2192.168.1.15:1300

Given that all the computers in the lab are directly connected to the same switch, and are not using any virtualization technology, at which of the following layers of the OSI model is the problem occurring?

A. Network
B. Application
C. Data link
D. Transport

Correct Answer: A

Explanation:
If we look at the Source Mac column, we can see two different MAC addresses. Every network interface card has a unique MAC address. These are the network cards in the two separate computers.
If we look in the Source IP column, we can see that the two network cards have been assigned the same IP address (192.168.1.10). This is the problem in this question. The error message on the screens will be saying that “An IP conflict exists”. Every network card connected to the network needs to be configured with a different IP address.
As the problem is with the IP address configuration of the two computers, we know that the problem is occurring at the Network layer (layer 3) of the OSI model. The network layer is responsible for Internet Protocol (IP) addressing and routing.

CompTIA Network+ Question A-39

When a client calls and describes a problem with a computer not being able to reach the Internet, in which of the following places of the OSI model would a technician begin troubleshooting?

A. Transport layer
B. Physical layer
C. Network layer
D. Session layer

Correct Answer: B

Explanation:
The bottom layer of the OSI reference model is Layer 1, the physical layer.
The physical layer is the layer that defines the hardware elements of a network. These elements include:
Network Interface Cards Network topology Network cabling
The type of signals used for data transmissions
When troubleshooting a network connectivity issue, the first thing you would check is the computer’s network cabling, the network card etc. In other words, the computer’s physical connection to the network.