Chapter 5 - Networks and Telecommunications

Question 1

Open Systems Interconnection Reference Model (OSI) Layers

Answer 1

Layer 1: Physical
Layer 2: Data link
Layer 3: Network
Layer 4: Transport
Layer 5: Session
Layer 6: Presentation
Layer 7: Application

Question 2

Function of Layer 1 of the OSI

Answer 2

Establishes and manages the physical transmission of data between network devices

Question 3

Function of Layer 2 of the OSI

Answer 3

Responsible for the transfer of data between adjacent nodes on a network segment using MAC addresses to identify devices

Question 4

Function of Layer 3 of the OSI

Answer 4

Routing and forwarding data packets between different networks, using IP addresses

Question 5

Function of Layer 4 of the OSI

Answer 5

Responsible for ensuring reliable end-to-end communications and maintenance between applications

Question 6

Function of Layer 5 of the OSI

Answer 6

Opens, closes, and manages sessions between end-user application processes

Question 7

Function of Layer 6 of the OSI

Answer 7

Ensures that data is formatted and encoded in a way that the application can understand. Includes tasks like data translation and encryption/decryption

Question 8

Function of Layer 7 of the OSI

Answer 8

Provides the protocols that end-user applications use to interact with the network. For example: HTTP for browsing the web and FTP for file transfer

Question 9

WAN

Answer 9

Wide-area network

Question 10

Example of a WAN

Answer 10

The internet

Question 11

Disadvantage of WANs

Answer 11

Data security cannot be guaranteed

Question 12

How can we make data more secure as it travels across a WAN

Answer 12

Encrypt it

Question 13

LAN

Answer 13

Local-area network

Question 14

Function of a LAN

Answer 14

Provide network connectivity for computers that are in the same geographic area and are typically connected with hubs and switches

Question 15

Hubs

Answer 15

devices that contain plugs and ports to connect ethernet cables for different network systems

Question 16

Switches

Answer 16

Receive packets of information, look at the destination MAC address, and then send the packet there. (perform intelligent filtering)

Question 17

Disadvantage of a LAN

Answer 17

Oftentimes, they do not protect themselves from each other. So if one becomes infected, malware can quickly spread to all the devices on the network

Question 18

Example of a LAN

Answer 18

Ethernet networks (the most common LAN)

Question 19

The ethernet standard

Answer 19

Defines how computers use media access control (MAC) addresses to communicate with each other

Question 20

The ethernet standard governs which layers of the OSI?

Answer 20

Physical (layer 1) and data link (layer 2)

Question 21

Virtual LANs

Answer 21

A collection of logically related network devices that are viewed as a network segment. Allows administrators the ability to separate network segments without physically separating the cabling

Question 22

Transmission control protocol (TCP) and internet protocol (IP) are apart of which layers of the OSI reference model?

Answer 22

Network and transport

Question 23

TCP and IP

Answer 23

a suite of protocols that govern all activity across the internet and through most corporate and home networks

Question 24

Network port

Answer 24

A number that tells a receiving device where to send messages it receives

Question 25

IPv4 addresses

Answer 25

4-byte, 32-bit; still the most common

Question 26

IPv6 addresses

Answer 26

128-bits long; more complex and secure

Question 27

Dynamic Host Configuration Protocol (DHCP)

Answer 27

Provides a computer with an IPv4 address, a subnet mask, and other essential communication information

Question 28

Internet Control Message Protocol (ICMP)

Answer 28

A management and control protocol for IP that delivers messages about the health of the network

Question 29

Vulnerability of ICMP

Answer 29

Attackers can use it to create a DoS attack

Question 30

Reconnaissance

Answer 30

Gathering information about a network for use in a future attack

Question 31

Eavesdropping

Answer 31

When an attacker taps a data cable to see all the data passing through it

Question 32

Denial-of-service (DoS)

Answer 32

Flooding a network with traffic and shutting down a single point of failure

Question 33

Distributed denial-of-service (DDoS)

Answer 33

Uses multiple compromised systems to flood the network from many different directions

Question 34

Telephony denial-of-service (TDoS)

Answer 34

Attempts to prevent telephone calls from being successfully initiated or received by some person or organization

Question 35

Firewalls

Answer 35

Controls the flow of traffic by preventing unauthorized network traffic from entering or leaving a particular portion of the network

Question 36

Border firewalls

Answer 36

Separate the protected network from the internet

Question 37

Three parts of Unified Threat Management

Answer 37

1. URL filter - filters web traffic by examining the URL instead of the IP 2. Content inspection - looks at network packet content to determine if the packet should be allowed to pass 3. Malware inspection - looks at packet content for signs of malware

Question 38

Network Access Control (NAC)

Answer 38

Enables you to add more security requirements before allowing a device to connect to the network

Question 39

Wireless access points (WAPs)

Answer 39

A radio that sends and receives networking information over the air between wireless devices and the wired network

Question 40

Who can attempt to connect to wireless access points?

Answer 40

Anyone who is in radio range

Question 41

Examples of wireless network security controls

Answer 41

- VPNs - Wireless encryption (such as WEP, CCMP, WPA) - MAC address filtering - SSID broadcast