Domain 4: Communication and Network Security

Question 1

Define:

10Base2

Answer 1

An Ethernet network standard also known as thin Ethernet or thinnet, with 10 Mbps data transfer rate, baseband signals, and supports cable lengths up to 185 meters using thin coaxial cables.

A specific type of Ethernet network standard characterized by a maximum data transfer rate of 10 Mbps, baseband transmission, and a maximum cable segment length of 185 meters. This standard, also known as thin Ethernet or thinnet, uses a thinner and more flexible coaxial cable, allowing for easier installation and management in environments such as office buildings.

For more information, view this lecture on Cable types.. Or visit this Wikipedia page.

Question 2

Define:

10Base5

Answer 2

Also called thick Ethernet, this standard supports 10 Mbps speed over baseband transmission, using thick coaxial cables with a maximum reach of 500 meters.

A specification for thick Ethernet, a networking standard that also operates at a data transfer rate of 10 Mbps but uses thicker, more rigid coaxial cables that can transmit data over a maximum distance of 500 meters. The name ‘10Base5’ is derived from its 10 Mbps speed, baseband transmission, and 500-meter cable limit. Due to its ability to handle greater distances, it’s often used in larger, more sprawling network setups.

For more information, view this lecture on Cable types.. Or visit this Wikipedia page.

Question 3

Define:

10BaseT

Answer 3

A form of Ethernet that uses twisted pair cabling to achieve 10 Mbps speed with baseband transmission, suited for star network configurations in small local networks.

An Ethernet standard that operates at 10 Mbps and uses baseband transmission over twisted pair cabling. The ‘T’ in 10BaseT stands for ‘Twisted pair,’ indicating the type of cabling used. It is designed for small, local networks and supports star network configurations, which centralize network control and allow easier detection of connection issues.

For more information, view this lecture on Cable types.. Or visit this Wikipedia page.

Question 4

Define:

3-Legged DMZ

Answer 4

A network layout that includes three distinct zones: the untrusted Internet, a demilitarized zone (DMZ) for public-facing services, and a trusted internal network for additional security.

A network design strategy that uses three security zones - the Internet (untrusted), an intermediary area known as the Demilitarized Zone (DMZ), and the internal network (trusted). The DMZ hosts public-facing services, acting as a buffer between the Internet and the internal network. This model adds an extra layer of protection by ensuring direct traffic between the Internet and the trusted network is minimized and strictly controlled.

For more information, view this lecture on Firewalls Part 2. Or visit this Wikipedia page.

Question 5

Define:

3-Way Handshake

Answer 5

The process used in TCP/IP networks to establish a connection between a client and server, involving sequential SYN, SYN-ACK, and ACK packets for reliable communication initiation.

A three-step process used in network communications to establish a connection between a client and a server in TCP/IP protocol. The handshake begins when the client sends a SYN (synchronize) packet to the server to request a connection. The server then responds with a SYN-ACK (synchronize-acknowledge) packet to acknowledge the request. Finally, the client sends an ACK (acknowledge) packet back to the server to confirm. Once this process is completed, the TCP connection is established, allowing for data transmission to take place. This handshake is essential for initiating a reliable session between two devices over a network.

For more information, view this lecture on MAC, HMAC, SSL, and TLS. Or visit this Wikipedia page.

Question 6

Define:

Access Point

(AP)

Answer 6

A device that connects wireless devices to a wired network, enabling communication and access to network resources, such as routers and wireless hotspots.

A device that connects wireless devices to a wired network, allowing them to communicate and access resources on the network. It is used in wireless networks to provide connectivity and access to network resources. Examples of access points include routers and wireless hotspots.

For more information, view this lecture on WiFi - Part 1. Or visit this Wikipedia page.

Question 7

Define:

Acknowledgment

(ACK)

Answer 7

A communication signal confirming successful data reception, used to maintain the reliability of communication systems.

A signal sent between devices during a communication process to confirm that data has been successfully received. Typically, an ACK is sent from the receiver back to the sender after a packet of data has been received. The use of acknowledgments helps to ensure the reliability of communication systems, as it allows for error detection and prompts retransmission of data if an ACK is not received within a certain time frame.

For more information, view this lecture on MAC, HMAC, SSL, and TLS. Or visit this Wikipedia page.

Question 8

Define:

Ad Hoc Mode

Answer 8

A wireless network configuration where devices connect directly to each other without a central access point, used for temporary network setups like peer-to-peer file sharing.

A wireless network mode where devices connect directly to each other without the use of a central access point. It is used in situations where a temporary network is needed, such as a group of friends sharing files at a party. Examples include Wi-Fi Direct, Bluetooth, and peer-to-peer networking.

For more information, view this lecture on WiFi - Part 2. Or visit this Wikipedia page.

Question 9

Define:

Address Resolution Protocol

(ARP)

Answer 9

A networking protocol used to map a network IP address to its corresponding physical MAC address, facilitating device communication on a local network.

a networking protocol that maps a network’s logical IP address to its physical MAC address. It is used to enable communication between devices on a network. Examples include ARP requests, and ARP replies in the process of resolving an IP address to a MAC address.

For more information, view this lecture on IP support protocols - Part 1. Or visit this Wikipedia page.

Question 10

Define:

Address Space

Answer 10

The range of memory addresses that can be used by a system or network, ensuring unique addressing for devices to communicate on a network.

The range of addresses that can be assigned to devices on a network. Address space refers to the range of IP addresses that can be assigned to devices on a network, including both IPv4 and IPv6 addresses. This is used in networking to ensure that each device on the network has a unique address and can communicate with other devices. It is used to identify and locate devices on a network.

For more information, view this lecture on IP addresses, MAC addresses, and port numbers- Part 1. Or visit this Wikipedia page.

Question 11

Define:

Address Space Layout Randomization

(ASLR)

Answer 11

A security technique that randomly arranges key data areas of a program in memory, making it more difficult for attackers to predict and exploit memory addresses.

A security technique that randomly arranges the positions of key data areas of a program—including the base of the executable and position of libraries, heap, and stack—in a process’s address space. By doing so, it makes it harder for an attacker to predict target addresses, thus mitigating the risk of exploitation techniques such as buffer overflow attacks. ASLR is widely used in modern operating systems to enhance their security posture.

For more information, view this lecture on Hardware architecture- Part 2. Or visit this Wikipedia page.

Question 12

Define:

Addressing

Answer 12

The process of assigning a unique identifier, such as an IP address, to network devices to enable communication and data packet routing.

In the context of computer networks, addressing refers to the assignment of a unique identifier to each device or destination on the network. This identifier, also known as an IP address, allows devices to communicate with each other and route data packets to their intended destination. Examples of addressing include the use of IP addresses in the Internet Protocol (IP) to identify computers on the Internet and the use of MAC addresses in local area networks (LANs) to identify individual network devices.

For more information, view this lecture on IP addresses, MAC addresses, and port numbers- Part 1..

Question 13

Define:

Alternative Routing

Answer 13

A network management method where traffic is redirected via a different path in case of primary route failure, congestion, or maintenance, ensuring continuous service.

A method used in telecommunications and network management where traffic is directed over a different path or route than the primary one in case of failure, congestion, or maintenance. Alternative routing aims to ensure that there is no interruption in service by having backup paths available. In sophisticated networks, routing protocols can automatically detect outages or suboptimal performance and switch to alternate routes in real time, maintaining consistent data flow and service availability. This concept is integral to network resilience and business continuity planning.

For more information, view this lecture on The OSI model- Part 1..

Question 14

Define:

Amplifiers

Answer 14

Devices that increase the signal strength in communication systems, used to enhance signal clarity and reach for both audio and radio transmissions.

Devices or systems that increase the strength or magnitude of a signal, such as an audio or radio signal. It is used in communication systems to boost the signal and improve its clarity and reach. Examples of amplifiers include audio amplifiers in speakers and microphones and radio frequency amplifiers in wireless transmitters and receivers.

For more information, view this lecture on Cable types.. Or visit this Wikipedia page.

Question 15

Define:

Analog

Answer 15

A method of signal transmission that varies continuously in response to changes in sound or light, used in traditional telephony and various audio systems, as opposed to digital signals.

In telecommunications, analog refers to the transmission of voice, video, or data through continuous signals that vary in frequency or amplitude in response to changes in sound or light. Traditional landline telephones, for instance, convert voice sounds into electrical signals that mimic the sound waves. These analog signals can be transmitted over copper wires and are subject to degradation from noise and distance, contrasting with digital signals, which can be more easily cleaned and amplified. While much of modern telecommunications has shifted toward digital technologies for their efficiency and fidelity, analog technology is still in use in various capacities, such as radio broadcasting and certain audio systems.

For more information, view this lecture on Networking basics and definitions.. Or visit this Wikipedia page.

Question 16

Define:

Anycast

Answer 16

A network addressing method where multiple servers share the same IP address, distributing traffic to improve performance and enhance redundancy.

A networking technique that allows multiple servers to share the same IP address, with the objective of distributing network traffic and improving availability and performance. When a user makes a request to an anycast IP address, the network routes the request to the nearest or best-performing server based on factors like geographic proximity, latency, and server load. This technique is widely used in content delivery networks (CDNs) and domain name system (DNS) services to ensure fast response times and resilience against outages or attacks.

Or visit this Wikipedia page.

Question 17

Define:

API Security

Answer 17

API Security focuses on safeguarding APIs from unauthorized access, data breaches, and exploitation. API Gateway Security provides central control and policy enforcement for managing traffic, authentication, threat detection.

API Security includes designing, implementing, and monitoring protective measures that prevent malicious activities and data leakage through APIs. It involves secure authentication, authorization, rate limiting, and data validation. An API Gateway acts as a single entry point for requests, enforcing policies, routing traffic, and blocking suspicious behavior. Centralizing these functions simplifies management and ensures consistent protection across multiple services. Effective API Security enhances reliability, preserves trust, and minimizes the risk of critical data exposure or unauthorized transactions.

Or visit this Wikipedia page.

Question 18

Define:

Application Layer

Answer 18

The 7th layer in the OSI model, interfacing directly with end-user applications, responsible for high-level protocols such as HTTP, FTP, and SMTP, and managing network communications.

In the Open Systems Interconnection (OSI) model, the application layer is the 7th layer, which interfaces directly with end-user software applications to manage network communications. It is responsible for high-level protocols such as HTTP for web browsing, FTP for file transfers, and SMTP for email. In the simpler TCP/IP model, the application layer is often conceptualized as layer 4, which encompasses the functionalities of the OSI’s application, presentation, and session layers. This topmost layer in the TCP/IP model enables user applications to interact with the network stack, ensuring that data is properly packaged for communication and interpreted upon receipt.

For more information, view this lecture on The OSI model- Part 2.. Or visit this Wikipedia page.

Question 19

Define:

Application-Level Gateway Firewall

Answer 19

A type of firewall that operates at the application layer of the network, inspecting the content of data packets to detect and filter out malicious traffic for improved security.

A type of firewall that operates at the application layer of a network’s protocol stack. It filters incoming traffic to certain network services like FTP and Telnet servers and can inspect the actual content of the data packets, not just the source, destination, and port. This allows for a more thorough examination of the packet payload to detect malicious code or protocols, offering a higher level of security compared to other types of firewalls.

For more information, view this lecture on Firewalls Part 1. Or visit this Wikipedia page.

Question 20

Define:

ARCNET

(Attached Resource Computer Network)

Answer 20

An early LAN technology known for simplicity and reliable deterministic performance.

ARCNET is one of the first local area network (LAN) technologies that provided a simple and robust network communication method. Known for its predictable performance and ease of installation, ARCNET was widely adopted in early computer networks. Although newer technologies have supplanted it, ARCNET’s fundamental principles influenced modern networking standards and provided a foundation for deterministic network design.

For more information, view this lecture on LAN topologies.. Or visit this Wikipedia page.

Question 21

Define:

Area Border Router

(ABR)

Answer 21

A router connecting different OSPF areas within a network, facilitating communication between them and identified by a unique Autonomous System Number (ASN).

A router that connects different OSPF (Open Shortest Path First) areas within a network. It is used to connect different OSPF areas and allow for communication between them. Examples include routers in a large enterprise network or a service provider network.

For more information, view this lecture on WAN protocols.. Or visit this Wikipedia page.

Question 22

Define:

ARP Spoofing/Poisoning

Answer 22

A type of cyberattack where false ARP messages are sent to a network, misleading devices to send data to an incorrect MAC address for intercepting traffic.

A cyber-attack where a malicious actor sends fake ARP (Address Resolution Protocol) messages to a network, tricking other devices into sending data to the wrong MAC (Media Access Control) address. It is used to intercept and modify network traffic, steal sensitive information, or launch further attacks. Examples include redirecting traffic to a fake website, intercepting login credentials, or injecting malware into downloads.

For more information, view this lecture on IP support protocols - Part 1.. Or visit this Wikipedia page.

Question 23

Define:

ARP Table

Answer 23

A table in each networked device that maps IP addresses to MAC addresses, essential for local network communication and routing.

The ARP Table, or Address Resolution Protocol Table, is a table stored in each device on a network, which maps IP addresses to MAC addresses. This table is essential for local network communication because while IP addresses are used for routing data over the network, MAC addresses are used for direct device-to-device communication within the network.

For more information, view this lecture on IP support protocols - Part 1.. Or visit this Wikipedia page.

Question 24

Define:

ARPANET

(Advanced Research Projects Agency Network)

Answer 24

The pioneering packet-switching network that laid the foundation for the modern Internet.

Developed in the late 1960s, ARPANET was the first operational packet-switching network that connected research institutions across the United States. It introduced innovative concepts in data communication, setting the stage for the development of the modern Internet. ARPANET’s architecture and protocols have had a lasting impact on subsequent network designs and global digital communications.

For more information, view this lecture on IP addresses, MAC addresses, and port numbers- Part 1.. Or visit this Wikipedia page.

Question 25

# Define: Asynchronous

Answer 25

Processes that do not occur simultaneously or require real-time responses, allowing independent and uninterrupted operation of tasks or communications. ## Footnote Refers to processes that do not occur at the same time or do not require immediate response, allowing operations to execute independently without waiting for preceding tasks to complete. In computing, asynchronous communication is where data can be transmitted intermittently rather than in a steady stream, with the sender and receiver operating at their own pace and not simultaneously. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Asynchrony_(computer_programming)).*

Question 26

# Define: Asynchronous Communication

Answer 26

Communication where parties do not interact in real-time, exchanging messages at different times for flexibility, such as emails or forum posts. ## Footnote A mode of communication where the parties involved do not need to interact with each other in real-time. Messages can be sent and received at different times, allowing for greater flexibility and convenience. This model is often used in email, discussion forums, and other platforms where instant response is not necessary. *For more information, view this lecture on [Secure Communications - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178318-secure-communications-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Asynchronous_communication).*

Question 27

# Define: Asynchronous Transfer Mode | (ATM)

Answer 27

A network technology using small fixed-sized cells for traffic data, suited for voice and video transmission due to consistent cell size. ## Footnote A networking technology that splits traffic data into small fixed-sized cells, contrary to other networking technologies, which use variable-size packets. ATM provides data link layer services that run over a wide range of networks. Its small, fixed-size cells are well suited for carrying voice and video traffic, as well as data, making it advantageous for multimedia transmission. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode).*

Question 28

# Define: Attenuation

Answer 28

The weakening of a signal as it travels through a medium, which can affect data transmission quality and leave communication susceptible to interception. ## Footnote The reduction in signal strength as it travels through a medium. In the context of networks, this refers to the reduction in signal strength that occurs as a signal is transmitted over distances, through cables, or via wireless. High attenuation can degrade the quality of data transmission and potentially expose the data to interception if not properly managed and mitigated. *For more information, view this lecture on [Cable types.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Attenuation).*

Question 29

# Define: Authentication Header | (AH)

Answer 29

A protocol in internet security for message sender authentication and protection against tampering or interception, part of the IPSec suite. ## Footnote A protocol used in internet security to authenticate the sender of a message and to protect the message from tampering or interception. It is used in conjunction with Internet Protocol Security (IPSec) to provide end-to-end security for Internet communications. For example, AH may be used to authenticate the sender of an email and to encrypt the contents of the message to protect against unauthorized access. *For more information, view this lecture on [IPSec and PGP.](https://courses.thorteaches.com/courses/take/cissp/lessons/19149746-ipsec-and-pgp). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Authentication_Header).*

Question 30

# Define: Authentication Server | (AS) (In Kerberos)

Answer 30

In Kerberos, the server providing initial credential verification and issuing a Ticket Granting Ticket (TGT) for secure network service access. ## Footnote In the Kerberos network authentication protocol, the Authentication Server is a key component that provides the initial verification of a principal's (user or service) credentials. When a principal attempts to authenticate, it communicates with the AS, which checks the provided information against a database of users. If the credentials are valid, the AS issues a Ticket Granting Ticket (TGT) encapsulated within a message that can only be decrypted by the principal's secret key. The TGT is then used to request access to other network services without resending the principal's credentials, improving security and efficiency. The AS's role is crucial in establishing a trusted basis for further secure communications within the Kerberos-protected network environment. *For more information, view this lecture on [Authentication protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19179828-authentication-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Kerberos_(protocol)).*

Question 31

# Define: Autonomous System | (AS)

Answer 31

A network of connected routing protocols controlled by one entity, managing internal routing and interfacing with external networks. ## Footnote A collection of connected internet routing protocols and devices that are managed and controlled by a single administrative entity. It is used to route traffic within a network and to other networks and to provide network services such as hosting and content delivery. Each AS is identified by a unique Autonomous System Number (ASN) used for routing decisions. *For more information, view this lecture on [Layer 3 routing protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Autonomous_system_(Internet)).*

Question 32

# Define: Autonomous System Number | (ASN)

Answer 32

A unique identifier for an Autonomous System used in internet routing to organize global infrastructure and manage traffic. ## Footnote A unique identifier assigned to each Autonomous System (AS) for use in internet routing. This number is used to organize and coordinate the global internet infrastructure, allowing for the establishment of unique routing policies and ensuring that data is efficiently and accurately directed across the web. *For more information, view this lecture on [Layer 3 routing protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Autonomous_system_(Internet)).*

Question 33

# Define: Backbone

Answer 33

The primary network infrastructure that carries the bulk of data traffic, connecting different nodes and ensuring efficient data transfer across locations. ## Footnote The primary network infrastructure within a system that carries data across different nodes. Typically, it comprises high-speed connectivity paths that enable efficient routing and data transfer across large geographical areas. In complex network architectures, the backbone forms the critical "spinal cord" connecting various subnetworks, supporting smooth and reliable operations. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Backbone_network).*

Question 34

# Define: Bandwidth

Answer 34

The maximum rate of data transfer across a network connection, affecting the speed and quality of data transmission, important for handling high data volumes. ## Footnote The maximum rate of data transfer across a given path or network connection, typically measured in bits per second (bps). The term is used to denote the capacity of a connection to handle data traffic, affecting the speed and quality of data transfer. High bandwidth is particularly important for the transmission of large volumes of data or for applications with real-time communication needs, such as video conferencing or online gaming. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bandwidth_(computing)).*

Question 35

# Define: Baseband

Answer 35

The original frequency range of a signal before modulation, used for direct digital signal transmission over a medium, common in local area networks. ## Footnote The original frequency range of a signal before it is modulated for transmission. In data communication, baseband transmission allows digital signals to be sent directly over the medium without modulation into higher frequency ranges. This type of transmission is common in wired local area networks, where the entire bandwidth of the cable is used for a single signal or multiple signals in a time-division multiplexing manner. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Baseband).*

Question 36

# Define: Bastion Host

Answer 36

A server placed in a network's DMZ to protect against external threats, acting as a secured entry point and typically hosting applications like proxy servers or VPN gateways. ## Footnote A server strategically placed in a network's DMZ (demilitarized zone) to defend against external threats. The bastion host serves as a strongly secured entry point into the network and typically hosts a single application like a proxy server or VPN gateway. *For more information, view this lecture on [Firewalls Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/33182521-firewalls-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bastion_host).*

Question 37

# Define: Baud Rate

Answer 37

A measure of data transmission speed over a communication channel, defined by the number of signal units per second and often equated to bits per second in digital systems. ## Footnote A measure of the speed of data transmission over a communication channel, defined as the number of signal units per second. It is often used interchangeably with bits per second (bps), but technically, baud rate refers to the number of times the condition of the line changes. For digital systems, this usually equates to the number of bits transmitted per second, influencing the speed and efficiency of data transmission. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Baud).*

Question 38

# Define: Bit Error Rate

Answer 38

The number of transmitted message bits that are incorrect, used as a reliability measure in communication systems, with a lower rate indicating higher transmission accuracy. ## Footnote the number of incorrect bits transmitted in a message, typically measured as a percentage. It is used in communication systems to measure the reliability of a transmission. For example, a bit error rate of 10^-6 means that out of every 1,000,000 bits transmitted, there will be, on average, one error. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bit_error_rate).*

Question 39

# Define: Bit Splitting

Answer 39

A security method dividing a single data bit into multiple parts distributed across different locations or paths, enhancing the difficulty for unauthorized data interception and assembly. ## Footnote A method used in data security and encryption where a single bit of data is divided into two or more separate bits. The split bits are then typically distributed across different storage locations or transmission paths. The purpose of bit splitting is to enhance security, since the original bit is not stored or transmitted whole, it becomes more difficult for unauthorized parties to intercept and piece together the complete data. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cryptographic_splitting).*

Question 40

# Define: Blind FTP

Answer 40

A form of FTP where the server permits file transfers without user login, often allowing anonymous access for public file distribution. ## Footnote A form of FTP where the server allows file transfers without requiring the user to log in with credentials. Typically, such servers are configured to permit anonymous access, often used for distributing files that are meant to be publicly available.

Question 41

# Define: Bluebugging

Answer 41

A Bluetooth exploit allowing unauthorized control over a mobile device. ## Footnote Bluebugging is a security vulnerability in Bluetooth-enabled devices where an attacker exploits weaknesses in the protocol to gain unauthorized access. This method can allow the attacker to intercept communications, control device functions, or retrieve sensitive information without the owner's knowledge. The risk posed by bluebugging underscores the need for robust Bluetooth security measures and regular firmware updates. *For more information, view this lecture on [Bluetooth](https://courses.thorteaches.com/courses/take/cissp/lessons/19178204-bluetooth). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bluebugging).*

Question 42

# Define: Bluejacking

Answer 42

Sending unsolicited messages or files to Bluetooth-enabled devices for wireless communication without direct connection, such as promotional messaging. ## Footnote The practice of sending unsolicited messages or files to Bluetooth-enabled devices. It is used in wireless communication to send short messages or files to nearby devices without the need for a direct connection. For example, Bluejacking can be used to send a promotional message to nearby phones with Bluetooth enabled. *For more information, view this lecture on [Bluetooth](https://courses.thorteaches.com/courses/take/cissp/lessons/19178204-bluetooth). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bluejacking).*

Question 43

# Define: Bluesnarfing

Answer 43

Unauthorized access to wireless devices via Bluetooth, allowing information theft from phones or laptops without the user's awareness, posing serious security concerns. ## Footnote A type of unauthorized access to a wireless device through a Bluetooth connection, often between phones, desktops, or laptops. This attack allows access to stored information, like email messages, contact lists, or calendars, without alerting the device's user. Unlike Bluejacking, which primarily involves sending unsolicited messages, Bluesnarfing is a serious security concern as it allows for theft of information and unauthorized access to personal data. *For more information, view this lecture on [Bluetooth](https://courses.thorteaches.com/courses/take/cissp/lessons/19178204-bluetooth). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bluesnarfing).*

Question 44

# Define: Bluetooth

Answer 44

A short-range wireless technology standard for data exchange between devices, designed for low power consumption and common in various hardware, with potential security vulnerabilities. ## Footnote A wireless technology standard used for exchanging data between fixed and mobile devices over short distances. It utilizes short-wavelength UHF radio waves and is primarily designed for low power consumption. Bluetooth has become a common feature in many types of hardware, from computers and smartphones to audio equipment and car audio systems. Like any wireless technology, it has potential vulnerabilities and can be exploited if not properly secured, such as in the case of Bluejacking or Bluesnarfing. *For more information, view this lecture on [Bluetooth](https://courses.thorteaches.com/courses/take/cissp/lessons/19178204-bluetooth). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bluetooth).*

Question 45

# Define: BOOTP | (Bootstrap Protocol)

Answer 45

A network protocol that automates the assignment of IP addresses during system startup. ## Footnote BOOTP is a legacy protocol used by network devices to automatically obtain an IP address and essential configuration parameters during the boot process. It enables devices to join a network and communicate without manual configuration. Although largely replaced by DHCP, BOOTP laid the groundwork for automated network configuration, simplifying the deployment of devices in early network infrastructures. *For more information, view this lecture on [IP support protocols - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/23142530-ip-support-protocols-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/BOOTP).*

Question 46

# Define: Bootstrap

Answer 46

The process that initializes a computer system and loads the operating system. ## Footnote Bootstrap refers to the self-starting procedure a computer system goes through upon powering up, which includes hardware initialization, firmware execution, and loading the operating system. This process is critical to transforming a powered-off system into a fully functional environment. Effective bootstrapping influences startup speed, stability, and the overall reliability of computing operations. *For more information, view this lecture on [IP support protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bootstrapping).*

Question 47

# Define: Border Gateway Protocol | (BGP)

Answer 47

The protocol managing internet packet routing by exchanging information between autonomous systems, determining optimal data packet delivery paths. ## Footnote The protocol that manages how packets are routed across the Internet by exchanging information between autonomous systems (ASes). BGP is used to determine the best available paths for data packet delivery and to maintain a table of IP network routes, which are dynamically updated in response to changes in the network. *For more information, view this lecture on [Layer 3 routing protocols](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Border_Gateway_Protocol).*

Question 48

# Define: Boundary

Answer 48

A defined barrier managing information flow between security domains, essential for restricting attack vectors and containing damage in case of breaches. ## Footnote In the context of system security, a boundary refers to the defined barrier between different security domains, helping to manage and restrict the flow of information. This could be physical, such as the walls of a secured server room, or logical, such as a firewall or other security device that filters network traffic. Properly managed boundaries are crucial in limiting potential attack vectors and containing any damage if a breach does occur. A system's boundary protection mechanisms should be defined based on the sensitivity of the information it handles and the potential threats it faces. *For more information, view this lecture on [Software vulnerabilities and Attacks](https://courses.thorteaches.com/courses/take/cissp/lessons/19182134-software-vulnerabilities-and-attacks).*

Question 49

# Define: Bridge

Answer 49

A network device connecting two different network segments to facilitate communication and data sharing, used to enhance connectivity and network performance. ## Footnote A network device that connects two different network segments, allowing them to communicate and share data. It is used in network architecture to increase connectivity and improve performance. Examples include a wireless bridge, a network bridge, or a virtual bridge. *For more information, view this lecture on [Layer 1 to 3 networking devices](https://courses.thorteaches.com/courses/take/cissp/lessons/19178219-layer-1-to-3-networking-devices). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bridging_(networking)).*

Question 50

# Define: Broadband Over Power Line | (BPL)

Answer 50

A data transmission method that uses the electrical power distribution infrastructure to provide internet connectivity, especially useful in areas lacking conventional telecommunications infrastructure. ## Footnote A method of data transmission that utilizes the existing electrical power distribution infrastructure to provide broadband internet connectivity. BPL is an alternative means of internet access that can be particularly useful in areas lacking conventional telecommunications infrastructure. *For more information, view this lecture on [Cable types](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Power-line_communication).*

Question 51

# Define: Broadband Transmission

Answer 51

The transfer of wide bandwidth data over a high-speed connection, allowing for simultaneous transportation of multiple signals and traffic types, essential for modern internet services. ## Footnote The transmission of wide bandwidth data over a high-speed internet connection. Broadband allows multiple signals and traffic types to be transported simultaneously, supporting a variety of services like voice, video, and data. It contrasts with the narrowband, which carries a single data type or signal. Broadband is essential for modern internet access. *For more information, view this lecture on [Networking basics and definitions](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Broadband).*

Question 52

# Define: Broadcast

Answer 52

The transmission of data packets to all devices on a network segment without differentiation, essential for network operations like address resolution but requiring control to prevent congestion. ## Footnote In networking, a broadcast refers to the transmission of data packets that are sent to all devices on a network segment. The broadcast is intended for all recipients within the broadcast domain and does not differentiate between individual devices. In a typical IP network, a broadcast address enables information to be simultaneously sent to every device on the local network. Broadcasts are essential for network operations like address resolution but must be controlled to prevent unnecessary traffic and potential network congestion. *For more information, view this lecture on [IP addresses, MAC addresses, and port numbers- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19177405-ip-addresses-mac-addresses-and-port-numbers-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Broadcasting).*

Question 53

# Define: Broadcast Domain

Answer 53

A network area where a broadcast packet can be delivered to all devices within it without routing, defined by the boundaries of routers and crucial in network design. ## Footnote A logical division of a computer network where any device can transmit a packet that can be delivered to all other devices without the need for routing. Broadcast domains are typically bounded by routers and are a fundamental concept in network design. *For more information, view this lecture on [The OSI model- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/22712043-the-osi-model-part-2). Or view this lecture on [Layer 1 to 3 networking devices](https://courses.thorteaches.com/courses/take/cissp/lessons/19178219-layer-1-to-3-networking-devices). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Broadcast_domain).*

Question 54

# Define: Broadcast Storm

Answer 54

A network issue caused by excessive broadcast messages, which can overwhelm and disrupt network functions, often due to configuration errors or malicious activities. ## Footnote A network issue that occurs when there are too many simultaneous broadcast messages in a network, causing the network to become overwhelmed and slow or even halting network functions. This could occur as a result of a configuration error, a malicious attack, or a feedback loop where broadcast messages are continually bounced back and forth between network devices. It's an example of a potential vulnerability that needs to be managed within broadcast domains. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Broadcast_radiation).*

Question 55

# Define: Bulk Data Transfer

Answer 55

The transfer of large volumes of data across networks, typically prioritizing volume over speed and efficiency, common in backups and data replication. ## Footnote The movement of large volumes of data across a network, typically used in contexts where speed and efficiency are less critical than the sheer volume of data being moved. This can be seen in backups or data replication between data centers. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_communication).*

Question 56

# Define: Bus

Answer 56

A data or power transfer subsystem between computer components, facilitating multi-point communication and data exchange within and outside a computer system. ## Footnote In the context of computing, a bus is a subsystem that transfers data or power between computer components or between computers. It is a shared communication link, used for exchanging data among multiple hardware components inside and outside the system. The use of a bus involves multipoint electrical paths, which allow data to be sent from one part of a computer to another. *For more information, view this lecture on [LAN topologies](https://courses.thorteaches.com/courses/take/cissp/lessons/19177530-lan-topologies). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bus_(computing)).*

Question 57

# Define: Bus Topology

Answer 57

A network design where devices are connected to a single communication line, which, if fails, can disable the entire network, valued for its simplicity and cost-effectiveness. ## Footnote A network design where each computer and network device are connected to a single cable or backbone. In this topology, information sent from a device moves in both directions along the backbone until it reaches its destination device. If the backbone fails, the entire network typically becomes unusable, highlighting the importance of regular checks and maintenance in these setups. Despite this drawback, bus topology is appreciated for its simplicity and cost-effectiveness, especially for small networks. *For more information, view this lecture on [LAN topologies](https://courses.thorteaches.com/courses/take/cissp/lessons/19177530-lan-topologies). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Network_topology).*

Question 58

# Define: BYOD | (Bring Your Own Device)

Answer 58

A policy allowing employee use of personal devices for work, introducing security risks mitigated by VPNs, antivirus software, and secure apps to protect data. ## Footnote A corporate policy allowing employees to use their personal electronic devices for work-related tasks. This approach can increase flexibility and employee satisfaction but also introduces security implications. Personal devices may not have the same stringent security controls as company-issued hardware, potentially exposing the network to malware or data breaches. To mitigate risks, businesses often implement BYOD security policies that include the use of VPNs, mandatory antivirus software, regular security updates, and the compartmentalization of company data through containerization or secure applications. These measures aim to safeguard sensitive information while accommodating the convenience of using personal devices. *For more information, view this lecture on [Mobile device security](https://courses.thorteaches.com/courses/take/cissp/lessons/19148750-mobile-device-security). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Bring_your_own_device).*

Question 59

# Define: Cable Modem

Answer 59

A network bridge device providing bi-directional data communication over radio frequency channels on a hybrid fiber-coaxial and RF over glass infrastructure, used for broadband Internet access. ## Footnote A type of network bridge that allows bi-directional data communication via radio frequency channels on a hybrid fiber-coaxial and radio frequency over glass infrastructure. Cable modems are primarily used to deliver broadband Internet access, leveraging the high bandwidth of a HFC and RFoG network. *For more information, view this lecture on [Modems](https://courses.thorteaches.com/courses/take/cissp/lessons/19178293-modems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cable_modem).*

Question 60

# Define: Cables

Answer 60

Physical paths used for data transmission between devices, such as Ethernet, coaxial, and fiber optic cables, each with specific properties and applications in networking. ## Footnote The physical paths used to transmit data between devices. They come in various types, including Ethernet cables, coaxial cables, and fiber optic cables, each with different data transmission speeds, noise resistance, and physical reach. Ensuring the appropriate selection and proper maintenance of cables is crucial for network efficiency and reliability. *For more information, view this lecture on [Cable types](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cable).*

Question 61

# Define: Callback

Answer 61

An authentication method where a server initiates a new connection to the user's registered contact information after an access request, adding an extra layer of security. ## Footnote In the context of secure communications, callback is a method of authenticating a user where a server initiates a new connection to the user's registered contact information (e.g., phone number or IP address) after receiving a request. This ensures that the access request is indeed coming from a trusted source. This method, though not widely used today due to more advanced techniques, adds an extra layer of security to verify the user's identity. *For more information, view this lecture on [Secure Communications - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/29462724-secure-communications-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Callback_(telecommunications)).*

Question 62

# Define: Captive Portal

Answer 62

A web page that users interact with before accessing a public network to perform actions such as authentication or acceptance of policies, often used to control access. ## Footnote A web page that a user must view and interact with before accessing a public network. Upon connecting to the network, the user's browser is redirected to the captive portal, which may require authentication, payment, acceptance of EULA/usage policies, or other actions from the user. Captive portals are commonly used in public Wi-Fi networks to control access and ensure security. *For more information, view this lecture on [WiFi - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178193-wifi-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Captive_portal).*

Question 63

# Define: Carrier Sense Multiple Access with Collision Avoidance | (CSMA/CA)

Answer 63

A protocol in wireless networks to prevent collisions by checking if the medium is free before transmitting data. ## Footnote A protocol used for controlling traffic in wireless networks to prevent collisions or simultaneous data transmissions that can cause data corruption. Before sending data, devices using CSMA/CA first check if the transmission medium is free. If it's occupied, the device waits for a random period before checking again, reducing the likelihood of multiple devices transmitting simultaneously and causing a collision. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_avoidance).*

Question 64

# Define: Carrier Sense Multiple Access with Collision Detection | (CSMA/CD)

Answer 64

A protocol that allows devices in a wired network to check for channel occupancy to avoid data collisions and ensure data integrity. ## Footnote A network protocol that operates at the data link layer (Layer 2) of the OSI model, which manages communication between devices in a wired network, such as Ethernet. The protocol allows devices to detect whether the shared communication channel is busy before attempting to transmit data, thus avoiding potential collisions. If a collision is detected, the devices involved will stop transmitting, wait for a random period, and then attempt to transmit again. This process continues until a successful transmission is achieved. CSMA/CD is crucial in ensuring effective communication and data integrity in networks where multiple devices are competing for bandwidth. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_detection).*

Question 65

# Define: Cellular Networks

Answer 65

Wireless communication networks using radio frequencies to transmit data between devices and infrastructure, used in mobile internet access and other services. ## Footnote A type of wireless communication network that uses radio frequencies to transmit data between mobile devices and the network operator's network infrastructure. Cellular networks are commonly used in smartphones and other mobile devices to provide access to the Internet, phone calls, and other services. Examples of cellular networks include GSM, LTE, and 5G networks. *For more information, view this lecture on [Wireless Networks](https://courses.thorteaches.com/courses/take/cissp/lessons/29462523-wireless-networks). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cellular_network).*

Question 66

# Define: Channel Service Unit/Digital Service Unit | (CSU/DSU)

Answer 66

Devices in telecommunications connecting customer's equipment with the public network, translating signals for reliable data transmission. ## Footnote Hardware devices used in digital telecommunications to connect the end customer's equipment with the public switched network. A CSU/DSU translates the digital signals produced by the customer's equipment into signals that can be transmitted over the carrier's network and vice versa. These devices are essential for enabling reliable data transmission over digital communication lines such as T1 and T3 connections. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/CSU/DSU).*

Question 67

# Define: Channels

Answer 67

Mediums through which data is transmitted, such as wires or wireless frequencies, requiring protection to ensure data security during transmission. ## Footnote In a communication context, channels refer to the medium through which data is transmitted from one place to another. This could include physical channels, such as wires or fiber optic cables, and wireless channels, such as those used in radio or infrared communication. From a security perspective, protecting these channels is essential to ensure that data is not intercepted, tampered with, or accessed by unauthorized individuals during transmission. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Channel_(communications)).*

Question 68

# Define: Circuit-Level Gateway Firewall

Answer 68

A firewall that operates at the session layer to manage connections and protect internal network details. ## Footnote A type of firewall that operates at the session layer of the OSI model, or the TCP/IP stack's equivalent, typically used to manage whether inside devices can connect to outside networks like the Internet. It creates a virtual circuit between the client and the server, hiding and protecting the network's internal characteristics and information by seeming to initiate all connections. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Circuit-level_gateway).*

Question 69

# Define: Circuit-Switched Network

Answer 69

A network establishing a dedicated path between two devices for the duration of a communication session. ## Footnote A type of network where a dedicated communication path is established between two devices before they start communicating. This path, or circuit, remains open for the duration of the communication session and is then terminated or "switched" once the session ends. Such networks are traditionally used for telephone communications, where a direct and constant connection helps ensure that the entire conversation arrives intact. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Circuit_switched_network).*

Question 70

# Define: Classless Interdomain Routing | (CIDR)

Answer 70

A method for IP address allocation and routing that replaced class-based systems, allowing more efficient use of IP space. ## Footnote A method for allocating IP addresses and routing Internet Protocol packets. It effectively replaced the previous system based on classes (Class A, B, and C) and allows for more efficient and flexible allocation of IP addresses. CIDR notation is a compact representation of an IP address and its associated routing prefix, helping reduce the size of routing tables and make more IP addresses available within organizations. *For more information, view this lecture on [IP addresses, MAC addresses, and port numbers- Part 3.](https://courses.thorteaches.com/courses/take/cissp/lessons/22874065-ip-addresses-mac-addresses-and-port-numbers-part-3). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing).*

Question 71

# Define: Client

Answer 71

A computer or program that requests information or services from a server within a network through a client-server architecture. ## Footnote A computer or device that accesses a server or network to request and receive information or services. Clients are typically connected to a server or network through a client-server architecture, where the client sends a request to the server, and the server responds with the requested information or service. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Client_(computing)).*

Question 72

# Define: Client/Server Network

Answer 72

An architecture where client devices request services from centralized servers, which provide resources or data in response. ## Footnote A network architecture where multiple client devices or programs connect to centralized servers to access services, resources, or share data. Servers provide various functionalities - like email, file storage, or web page hosting - while clients make requests to servers to utilize these services. This model is foundational to modern computing and the Internet. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Client%E2%80%93server_model).*

Question 73

# Define: Coaxial Cable

Answer 73

An electrical cable with a central conductor surrounded by an insulating layer and a metallic shield, used for data and voice communications. ## Footnote A type of electrical cable consisting of a central conductor surrounded by an insulating layer over which a metallic shield is placed. This construction is then enclosed in an outer insulating layer. Coaxial cables are used to transmit data, video, and voice communications, they are known for their ability to shield signals from external electromagnetic interference, making them suitable for a range of telecommunications and networking applications. They have been widely used for cable television and internet service connections. *For more information, view this lecture on [Cable types.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Coaxial_cable).*

Question 74

# Define: Collaborative Computing

Answer 74

The use of interconnected systems allowing users to collaborate, often in real time, and relying on secure practices to mitigate data leakage and unauthorized access. ## Footnote The use of interconnected computer systems and software to allow users to work together, often in real-time, toward a shared goal. This could include tools like shared documents, chat programs, or video conferencing. As collaboration often happens over networks, secure practices are crucial to prevent unauthorized access, data leakage, and other security threats. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Collaborative_software).*

Question 75

# Define: Collision - Networking

Answer 75

An event where multiple data packets sent from different devices on the same network segment interfere with one another. ## Footnote In computer networking, a collision is an event where multiple data packets transmitted from different devices collide on a network segment. Collisions occur in half-duplex networks, typically Ethernet, leading to packet loss and requiring retransmission. To minimize collisions, collision detection algorithms like CSMA/CD (Carrier Sense Multiple Access with Collision Detection) are employed. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Collision_domain).*

Question 76

# Define: Collision Domain

Answer 76

A network segment where data packets may collide during simultaneous transmissions. ## Footnote A Collision Domain is a section of a network in which data packets transmitted by devices might interfere with one another, leading to collisions. These collisions can reduce network performance and efficiency, particularly in shared medium networks. Effective network design, using devices like switches or routers, is essential for segmenting collision domains, thereby minimizing collisions and ensuring smooth data flow. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Collision_domain).*

Question 77

# Define: Command-Line Interface | (CLI)

Answer 77

A user interface for interacting with software or operating systems using text commands, useful for automation and troubleshooting. ## Footnote A user interface that allows users to interact with an operating system or software by typing text-based commands. It can provide a powerful tool for automating tasks, running scripts, or directly interacting with system files. In the hands of a skilled professional, the CLI can be an effective tool for system maintenance and troubleshooting, but it can also be a vector for executing malicious commands if accessed by an unauthorized user. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Command-line_interface).*

Question 78

# Define: Connectionless

Answer 78

A network communication method where packets are sent between devices without establishing a dedicated connection. ## Footnote A type of network communication where data packets are sent from one device to another without establishing a dedicated connection, allowing for quick data transmission. However, packets may arrive out of order or get lost, as there is no assurance of delivery, making it less reliable than connection-oriented services. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Connectionless_communication).*

Question 79

# Define: Connection-Oriented

Answer 79

A network communication approach that involves establishing a dedicated connection path before transmitting data. ## Footnote A network communication type that establishes a dedicated connection path before data is transmitted. This ensures reliable and ordered delivery of packets from sender to receiver. Protocols like TCP use a connection-oriented approach to guarantee that data is received accurately and completely. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Connection-oriented_communication).*

Question 80

# Define: Contamination

Answer 80

The introduction of unwanted elements like malware into a system, leading to potential data corruption and system disruptions. ## Footnote In the context of security, contamination refers to the unintentional introduction or infiltration of unwanted elements, such as malware or erroneous data, into a system or network. This can lead to data corruption, system disruption, or other adverse effects that may compromise the integrity and reliability of the system.

Question 81

# Define: Content Distribution Network | (CDN)

Answer 81

A network of servers that delivers internet content rapidly by caching it at various locations close to users. ## Footnote A geographically distributed network of servers and data centers that work together to provide fast delivery of internet content. By caching content at the network edge, closest to users, it minimizes latency and accelerates site load times, making it particularly useful for handling heavy content such as video or during traffic spikes. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 5](https://courses.thorteaches.com/courses/take/cissp/lessons/29450175-virtualization-cloud-and-distributed-computing-part-5). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Content_delivery_network).*

Question 82

# Define: Content Filtering

Answer 82

The practice of blocking or allowing content based on rules to comply with policies, protect users, and manage network resources. ## Footnote The practice of blocking or allowing content based on specific criteria to enhance user safety, improve network efficiency, or comply with company policies. It is commonly used in email systems to filter out spam or malicious emails and in web filters to restrict access to inappropriate or harmful websites. *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Content-control_software).*

Question 83

# Define: Content Inspection

Answer 83

An analysis method examining data content to detect threats and policy violations, looking beyond metadata at the actual content. ## Footnote An in-depth analysis method used to examine data, such as emails, web pages, or files, to detect threats that might not be noticed by traditional defense mechanisms. This involves looking beyond just the metadata and examining the actual content for potentially harmful substances, like malware or violations of policy guidelines. *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/End-to-end_encryption#Compliance_and_regulatory_requirements_for_content_inspection).*

Question 84

# Define: Contention-Based Protocols

Answer 84

Networking protocols allowing device access in a manner where conflicts may occur, like CSMA/CD for Ethernet networks. ## Footnote Network protocols that allow multiple devices to access the network medium in a manner where conflicts could occur. If two or more devices try to transmit data at the same time, a collision can occur, causing the data to become corrupt. Protocols like CSMA/CD (Carrier Sense Multiple Access/Collision Detection) used in Ethernet networks are examples of contention-based protocols. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Contention-based_protocol).*

Question 85

# Define: Control Bits

Answer 85

Small sequences of bits used to direct and manage data communication processes. ## Footnote Control Bits are binary digits embedded in data frames or protocol headers that instruct devices on managing data transmission, error checking, synchronization, and flow control. They play a fundamental role in ensuring that communication protocols function correctly by signaling operational commands. Accurate handling of control bits is essential for maintaining reliable, orderly data exchanges and efficient network operations. *For more information, view this lecture on [The OSI model- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/22712043-the-osi-model-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_segment_structure).*

Question 86

# Define: Control Plane

Answer 86

The segment of a network device that manages routing decisions and traffic policies. ## Footnote The Control Plane is responsible for the decision-making processes in a network device, including creating and updating routing tables, managing network policies, and establishing optimal paths for data flow. It provides directives to the forwarding plane, ensuring that packets are handled according to the configured parameters. Effective control plane operations are key to maintaining network stability, scalability, and adaptability. *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Control_plane).*

Question 87

# Define: Convergence

Answer 87

The interoperation of different technologies, systems, or services, leading to new, integrated forms and user experiences. ## Footnote The process where different technologies, systems, or services come together and interoperate, leading to new forms or unified experiences. In IT, it often refers to the blending of telecommunications, computing, and broadcasting into integrated solutions. Convergence is also seen in devices like smartphones, which combine phone service, internet access, and multimedia capabilities. *For more information, view this lecture on [Layer 3 routing protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Convergence_(routing)).*

Question 88

# Define: Convergence In Routing

Answer 88

The process where all routers in a network come to a consistent view of the network topology, ensuring proper packet routing. ## Footnote In the context of network routing protocols, convergence refers to the state where all routers within a network have a consistent view of the network topology. This uniform understanding enables routers to properly direct packets to their destination without routing loops or inconsistencies. Convergence time is crucial in dynamic networks where changes occur frequently, and it's the period it takes for all routers to learn about the changes and reach a state of agreement. Protocols such as OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol) have mechanisms to achieve convergence efficiently and maintain an accurate and stable routing environment within and between networks. Converged networks can lead to more efficient resource utilization and improved communication performance. *For more information, view this lecture on [Layer 3 routing protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Convergence_(routing)).*

Question 89

# Define: Cookie

Answer 89

Data sent from a website and stored by the user's browser, used to remember information and record browsing activity. ## Footnote A small piece of data sent from a website and stored on the user's computer by the web browser while the user is browsing. Cookies are designed to be a reliable mechanism for websites to remember stateful information or to record the user's browsing activity. They can also be used for remembering pieces of information that the user previously entered into form fields, such as names, addresses, passwords, and credit card numbers. *For more information, view this lecture on [Type 2 authentication - "Something you have" or "Possession factors"](https://courses.thorteaches.com/courses/take/cissp/lessons/19178858-type-2-authentication-something-you-have-or-possession-factors). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/HTTP_cookie).*

Question 90

# Define: Counter Mode with Cipher Block Chaining Message Authentication Code Protocol | (CCMP)

Answer 90

A wireless network security protocol combining AES encryption with CCM mode to ensure data confidentiality and integrity. ## Footnote A security protocol used in wireless networks to encrypt data and ensure its authenticity. It is a combination of the AES encryption algorithm and the CCM mode of operation, which provides both confidentiality and integrity for data transmitted over a wireless network. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/CCMP_(cryptography)).*

Question 91

# Define: Crosstalk

Answer 91

Interference where a transmitted signal creates an unwanted effect on another circuit or channel. ## Footnote An electromagnetic interference phenomenon where a signal transmitted on one circuit or channel creates an unwanted effect on another circuit or channel. In telecommunications and networking, crosstalk can lead to degradation of signal quality, resulting in communication errors or loss of data. It is more prevalent in older or improperly shielded cables and is a significant consideration in the design of high-speed data communication systems. Measures such as using twisted pair cables or proper cable management practices are employed to minimize crosstalk. *For more information, view this lecture on [Cable types.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Crosstalk).*

Question 92

# Define: Cyclic Redundancy Check | (CRC)

Answer 92

A technique for detecting errors in digital data by applying a mathematical algorithm to produce a checksum for verification. ## Footnote A method used to detect errors in digital data. It involves applying a mathematical algorithm to the data to produce a CRC value, which acts as a checksum. When data is transmitted or stored and then retrieved, a new CRC value is calculated and compared to the original. If the two values do not match, it indicates that an error has occurred in the data. CRC is a common technique for ensuring the integrity of data in computer networks, storage devices, and error-checking protocols. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cyclic_redundancy_check).*

Question 93

# Define: Dark Web

Answer 93

A hidden network of encrypted websites accessible only through specialized software. ## Footnote The Dark Web is a concealed layer of the internet not indexed by standard search engines, accessible via tools like Tor. It offers anonymity for users, hosting both legitimate privacy-focused content and illicit activities. While it enables free expression in restrictive environments, its association with criminal activities poses challenges for law enforcement and cybersecurity professionals, requiring nuanced strategies for monitoring and regulation. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dark_web).*

Question 94

# Define: Data Circuit Terminating Equipment | (DCE)

Answer 94

Devices connecting data terminal equipment to a transmission circuit, such as modems or routers, requiring security measures. ## Footnote Devices that act as an interface between data terminal equipment (DTE) and a data transmission circuit. These devices could include modems, switches, and routers. DCE devices provide a point of connection for networking and facilitate the communication process. Securing these devices is crucial as they can be potential points of exploitation by threat actors. *For more information, view this lecture on [Modems.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178293-modems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_circuit-terminating_equipment).*

Question 95

# Define: Data Communications

Answer 95

Transmitting and receiving data between points, including securing transmissions to ensure integrity and confidentiality. ## Footnote The process of transmitting and receiving digital or analog data between two or more points. The data can be transferred through various mediums like wire, optical fiber, or airwaves and can be anything from simple text files to complex multimedia presentations. Secure data communications are pivotal for maintaining the integrity and confidentiality of transmitted data. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_transmission).*

Question 96

# Define: Data Flow

Answer 96

The transfer of data through a system, important for understanding how data is processed and utilized in software and networks. ## Footnote The movement or transfer of data through a system, from one component or process to another, often visualized in diagrams to represent the path that data takes through software, systems, or networks. Data flow analysis is crucial in designing systems for efficiency and understanding how data is processed and utilized. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dataflow).*

Question 97

# Define: Data Flow Control

Answer 97

Regulating data transfer rates in networks to prevent recipient or channel overload, enhancing reliable data transfer. ## Footnote Mechanisms that regulate the rate at which data is sent or received in a network to avoid overwhelming a recipient or communications channel. This ensures reliable data transfer and efficient use of network resources and can enhance overall system performance. Flow control can be implemented via software at the application, transport, or network layers and is integral to network protocols like TCP. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Flow_control_(data)).*

Question 98

# Define: Data Link Layer

Answer 98

The OSI model's second layer that handles data transfer between adjacent network nodes with protocols for error-free transmission. ## Footnote The second layer of the OSI model handles the transfer of data between adjacent network nodes within a wide area network (WAN) or between nodes on the same local area network (LAN) segment. It encompasses the protocols and methods used to ensure an error-free transmission through physical addressing, data framing, network topology, error detection, and handling retransmissions. The Data Link Layer is subdivided into two sublayers - the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_link_layer).*

Question 99

# Define: Data Packet

Answer 99

A formatted unit of data carried by a packet-switched network, containing payload data and control information for routing to its destination. ## Footnote A unit of data made into a single package that travels along a given network path. Packets are used to transport user data and control information in systems based on packet switching, such as the Internet. Each packet contains the source and destination addresses along with payload data. Packets are routed through networks to their destination, where they are reassembled into the original message. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Network_packet).*

Question 100

# Define: Data Terminal Equipment | (DTE)

Answer 100

A device at the user end that serves as a source or destination for data, communicating with network equipment. ## Footnote A device at the user end of a communication link that serves as a data source, destination, or both. This can include devices like computers, printers, and terminals. DTEs communicate with data circuit-terminating equipment to establish, maintain, and terminate communication sessions and to manage the data exchange between them. *For more information, view this lecture on [Modems.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178293-modems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_terminal_equipment).*

Question 101

# Define: Datagram

Answer 101

Independent packets of data with necessary information for routing from source to destination, enabling flexible network communication. ## Footnote A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between these source and destination machines and the transporting network. This means that each piece of data can take a different path to reach its intended destination, which can be useful for handling network congestion and ensuring data transmission even if parts of the network are compromised. *For more information, view this lecture on [The OSI model- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Datagram).*

Question 102

# Define: Deencapsulation

Answer 102

Removing headers or upper layers from data packets during transmission, performed by the receiving system to interpret data. ## Footnote The process of removing headers or top layers from a packet, frame, or other data transmission unit during its journey through a network's layers in accordance with the layered architecture models such as OSI or TCP/IP. This action is taken by the receiving end of a data transmission to uncover the original data and interpret it correctly. *For more information, view this lecture on [The TCP-IP model.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177306-the-tcp-ip-model). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Encapsulation_(networking)).*

Question 103

# Define: Deep Packet Inspection | (DPI)

Answer 103

Deep Packet Inspection examines the header and payload of data packets for security checks, compliance enforcement, or traffic management, going beyond basic firewall capabilities. ## Footnote Unlike simple packet filtering, DPI can identify application-layer protocols, detect malicious payloads, or enforce content policies. Organizations use DPI to block malware, prevent data exfiltration, or shape network traffic. Privacy concerns arise if DPI is used for invasive monitoring, fueling debates about balancing security and individual rights. Properly deployed, DPI helps detect sophisticated threats and ensures regulated network usage while necessitating careful oversight and governance. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Deep_packet_inspection).*

Question 104

# Define: Default Deny Policy

Answer 104

Blocking all network traffic or access requests by default unless explicitly approved, enhancing security. ## Footnote A security strategy where all network traffic or access requests are automatically blocked unless they have been explicitly approved. This approach significantly reduces the risk of unauthorized access or data breaches as it requires explicit permission for any action, but it can also increase administrative overhead due to the necessity of frequent permissions adjustments. *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1).*

Question 105

# Define: Default Gateway

Answer 105

A network node that serves as an access point for local network devices to communicate with external networks or the Internet. ## Footnote The device that provides a connection point for devices on a network to communicate with other networks or the Internet. It serves as the routing path for network traffic that's heading outside the local network and is typically a router or other networking device that has the capability to interface with larger networks. *For more information, view this lecture on [IP support protocols - Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Default_gateway).*

Question 106

# Define: Demilitarized Zone | (DMZ)

Answer 106

A network zone that separates an internal network from an untrusted external network, usually the Internet. ## Footnote A physical or logical subnetwork that separates an organization's internal network from an untrusted network, usually the Internet. By placing servers that interact directly with the external environment, such as web servers or email servers, in the DMZ, an additional layer of security is established that helps protect the more sensitive internal systems from unauthorized access or attacks. *For more information, view this lecture on [Firewalls Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/33182521-firewalls-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/DMZ_(computing)).*

Question 107

# Define: Demodulation

Answer 107

Extracting the original information from a modulated carrier wave, a key function in telecommunications. ## Footnote The process of extracting the original information-bearing signal from a carrier wave. A demodulator takes a modulated carrier signal, which has specific characteristics set by a modulating signal, and converts it back into its original form or something close to it. It is the reverse process of modulation, which is used to encode information onto a carrier wave for transmission. Demodulation is a key function in radio receivers, televisions, and other telecommunications and data communication systems. *For more information, view this lecture on [Modems.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178293-modems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Demodulation).*

Question 108

# Define: Dense-Wave Division Multiplexer | (DWDM)

Answer 108

A technology that increases data transmission capacity by using multiple wavelengths on a single fiber. ## Footnote An optical technology utilized in communications to multiply the number of wavelengths that can be sent over a single optical fiber, thereby increasing the overall data transmission capacity. DWDM systems have the potential to transmit up to 80 wavelengths on a single fiber, providing a high-bandwidth solution for networks and reducing the risk of data congestion and delay. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dense_Wavelength_Division_Multiplexing).*

Question 109

# Define: DHCP Server

Answer 109

A network server that dynamically assigns IP addresses and configurations to devices. ## Footnote A DHCP Server automates the assignment of IP addresses, subnet masks, gateways, and other network settings to devices as they connect to a network. This automation streamlines network management, reduces configuration errors, and enhances connectivity by ensuring efficient, timely allocation of network resources across dynamic environments. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol).*

Question 110

# Define: Dial Back

Answer 110

A security mechanism in remote authentication that reconnects to a user via a known, pre-configured number. ## Footnote A security mechanism often used in remote authentication systems where the system disconnects a user after initial identification and then reconnects by dialing a pre-configured number. This process ensures that the connection is being established with a trusted source, thus reducing the risk of unauthorized access. It can be used in both telecommunications and networking environments to enhance security during remote access. *For more information, view this lecture on [Secure Communications - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/29462724-secure-communications-part-2).*

Question 111

# Define: Diameter

Answer 111

An AAA protocol that is an upgrade from RADIUS, predominantly used in mobile IP-based networks. ## Footnote Diameter is an authentication, authorization, and accounting (AAA) protocol designed as an upgrade to RADIUS. While it offers advancements like better security, scalability, and flexibility, Diameter is predominantly employed in mobile IP-based networks rather than replacing RADIUS in all contexts. RADIUS remains widely used, particularly in traditional network environments. *For more information, view this lecture on [Authentication protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19179828-authentication-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Diameter_(protocol)).*

Question 112

# Define: Digital Signals

Answer 112

Signals represented by binary values, offering secure and high-quality information transmission. ## Footnote A type of signal that is represented by discrete, separate values typically in binary format (0s and 1s). These signals are less susceptible to noise and distortion compared to their analog counterparts, ensuring a higher quality and more secure transmission of information in applications like telecommunications, computing, and data storage. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Digital_signal).*

Question 113

# Define: Digital Subscriber Line | (DSL)

Answer 113

Technology for high-speed internet access using telephone lines, faster than dial-up service. ## Footnote A type of communication medium used for transmitting digital data over telephone lines. It allows for fast data transfer speeds, providing an internet service that is significantly faster than traditional dial-up. This technology makes use of standard copper phone lines and is widely used in homes and businesses around the world. *For more information, view this lecture on [Secure Communications - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178318-secure-communications-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Digital_subscriber_line).*

Question 114

# Define: Directional Antenna

Answer 114

An antenna designed to focus radio signals in a particular direction, optimizing communication. ## Footnote A type of antenna that is designed to focus the radio signal in a particular direction. Unlike omnidirectional antennas that transmit and receive signals in all directions, directional antennas concentrate the signal in a specific area, which can significantly extend the range and improve the quality of the transmission. They are commonly used for point-to-point communication, including radio and television broadcasting, cellular communications, satellite communication, and wireless bridges. The focused signal also adds the benefit of reduced interference from unwanted sources outside of the target path. *For more information, view this lecture on [IP addresses, MAC addresses, and port numbers- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177405-ip-addresses-mac-addresses-and-port-numbers-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Directional_antenna).*

Question 115

# Define: Distance-Vector Routing Protocol

Answer 115

A routing protocol using distance metrics to determine the best path, relying on local router information exchanges. ## Footnote A network routing protocol that uses metrics or distances to determine the best path for data delivery. Each router using this protocol communicates with its neighbors to exchange information about the entire network topology. If changes are detected, updates are sent to all routers in the network, which helps prevent routing loops and provides a reliable delivery path. *For more information, view this lecture on [Layer 3 routing protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178251-layer-3-routing-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Distance-vector_routing_protocol).*

Question 116

# Define: Distributed Denial-of-Service Attack | (DDoS)

Answer 116

An attack aiming to overwhelm a targeted server or network with excessive traffic, using compromised systems, to disrupt normal operations. ## Footnote A malicious attempt to disrupt normal traffic to a targeted server, service, or network by overwhelming the target or its surrounding infrastructure with a flood of internet traffic. DDoS attacks are performed using multiple compromised computer systems as sources of attack traffic, which could include computers and other networked resources such as IoT devices. The influx of incoming messages, connection requests, and malformed packets can cause the target system to slow down or crash, denying service to legitimate users. DDoS attacks are a powerful weapon on the Internet and can be difficult to defend against, requiring sophisticated countermeasures. *For more information, view this lecture on [Risk- Attackers and Types of Attacks Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18588139-risk-attackers-and-types-of-attacks-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Denial-of-service_attack).*

Question 117

# Define: Distributed Network Protocol | (DNP3)

Answer 117

A communication protocol for data acquisition and control equipment, supporting the management of smart grids and SCADA systems. ## Footnote Distributed Network Protocol 3 (DNP3) is an open, standards-based protocol used primarily for communications between various types of data acquisition and control equipment. It is widely used in utilities and industrial automation systems to support the management of smart grids, SCADA systems, and other telemetry and control applications. DNP3 facilitates reliable and secure communication for monitoring and controlling networked devices. *For more information, view this lecture on [Industrial Control Systems.](https://courses.thorteaches.com/courses/take/cissp/lessons/19121862-industrial-control-systems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/DNP3).*

Question 118

# Define: Diverse Routing

Answer 118

Using multiple distinct data paths for networking, improving reliability by mitigating the risk of single points of failure. ## Footnote A technique implemented in networking to ensure that data can follow multiple distinct paths between sender and receiver. Having multiple possible routes mitigates the risk of network failure or congestion due to a single point of failure, increasing the reliability and availability of data transmission and reducing potential downtimes. *For more information, view this lecture on [Layer 1 to 3 networking devices.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178219-layer-1-to-3-networking-devices).*

Question 119

# Define: DKIM | (DomainKeys Identified Mail)

Answer 119

DKIM is an email validation protocol using cryptographic signatures to verify the sending domain’s authenticity, helping reduce phishing and spoofed communications. ## Footnote In DKIM, an organization’s mail server attaches a digital signature in the email header, linked to a public key stored in DNS records. Receiving servers validate the signature to confirm message integrity and authorship. Coupled with other standards like SPF, DKIM strengthens email security. Correct implementation fosters trust, minimizing fraudulent impersonation or tampering, and improving overall inbox deliverability. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail).*

Question 120

# Define: DLCI | (Data Link Connection Identifier)

Answer 120

A numeric label used in frame relay networks to identify virtual circuits. ## Footnote The Data Link Connection Identifier (DLCI) is a unique number assigned in frame relay networks to differentiate between multiple virtual circuits sharing the same physical link. It ensures accurate data routing by identifying the correct circuit for each packet transmitted. Proper management of DLCIs is vital for network efficiency, allowing for reliable segmentation and prioritization of data in shared environments. *For more information, view this lecture on [WAN protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177534-wan-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_link_connection_identifier).*

Question 121

# Define: DMARC | (Domain-Based Message Authentication, Reporting And Conformance)

Answer 121

An email authentication protocol to prevent domain spoofing and phishing. ## Footnote DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email security standard that utilizes SPF and DKIM records to validate incoming messages. It instructs receiving servers on how to handle emails that fail authentication checks and provides reporting mechanisms for unauthorized activity. DMARC enhances email security, reduces phishing risks, and improves overall trust in sender identity, ensuring robust protection for digital communications. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/DMARC).*

Question 122

# Define: DNSSEC | (Domain Name System Security Extension)

Answer 122

Extensions securing DNS against tampering and spoofing by using digital signatures and encryption. ## Footnote A security extension for the DNS protocol, which uses digital signatures and encryption to protect DNS records from tampering and spoofing. It is commonly used to secure DNS transactions and prevent attacks such as DNS poisoning. For example, a company may implement DNSSEC on their DNS servers to protect against attackers altering their DNS records and redirecting users to fake websites. *For more information, view this lecture on [IP Support Protocols - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/23142530-ip-support-protocols-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Domain_Name_System_Security_Extensions).*

Question 123

# Define: Domain Name System | (DNS)

Answer 123

The system that translates human-memorable domain names to IP addresses for locating network services and devices. ## Footnote A hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols. *For more information, view this lecture on [IP Support Protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Domain_Name_System).*

Question 124

# Define: Domain Name System (DNS) Exfiltration

Answer 124

A cyberattack method using DNS protocols to stealthily move data out of a compromised network, bypassing security measures. ## Footnote DNS exfiltration is a cyberattack method where attackers use the DNS protocol to stealthily move data from a compromised network to their own systems. Because DNS requests are common in network traffic and often allowed out of networks, attackers can covertly encode data within these requests, bypassing many security measures that do not scrutinize DNS traffic for such anomalies.

Question 125

# Define: Domain Name System (DNS) Poisoning

Answer 125

Manipulating DNS cache to redirect queries to malicious destinations, used for phishing or other malicious activities. ## Footnote A type of security exploit where an attacker redirects a DNS query to a different destination, typically a malicious website, by contaminating the DNS cache data of a DNS resolver with incorrect IP address entries. The attacker's goal is to control the mapping of domain names to IP addresses to lead users astray, often for phishing or other malicious purposes. *For more information, view this lecture on [IP Support Protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/DNS_spoofing).*

Question 126

# Define: Dual-Homed Host/Firewall

Answer 126

A security component with interfaces connected to both a secure internal network and an unsecured external network for traffic control. ## Footnote A security component that serves as a bridge between two networks, typically a secure internal network and an unsecured external network like the Internet. The dual-homed host has two network interfaces, with each connected to a separate network. It manages and controls the flow of traffic between these networks, mitigating the risk of unauthorized access or data breaches. *For more information, view this lecture on [Firewalls Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/33182521-firewalls-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dual-homed#In_firewalls).*

Question 127

# Define: Dynamic Host Configuration Protocol | (DHCP)

Answer 127

A protocol assigning IP addresses and network parameters dynamically to enable device communication on IP networks. ## Footnote A network management protocol used on IP networks where a DHCP server dynamically assigns an IP address and other network configuration parameters to each device on the network so they can communicate with other IP networks. DHCP eliminates the need for manually assigning IP addresses to all network devices, simplifying the process of connecting devices to the network and managing the allocation of IP addresses within a network. *For more information, view this lecture on [IP Support Protocols - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/23142530-ip-support-protocols-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol).*

Question 128

# Define: Dynamic Packet Filtering

Answer 128

A firewall security measure that monitors network traffic in real-time to adaptively manage data flow. ## Footnote A security measure used in network firewalls to manage the flow of network traffic in real-time. Unlike static packet filtering, which only examines a packet based on predefined rules, dynamic packet filtering evaluates packet information within the context of the packet's state or connection, providing a more adaptive and sophisticated approach to network security. *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Stateful_firewall).*

Question 129

# Define: Dynamic Ports

Answer 129

Network ports assigned temporarily for client-side TCP or UDP communications, facilitating short-term sessions. ## Footnote Also known as private or ephemeral ports, these are network ports assigned on an as-needed basis by a host's operating system for client-side TCP or UDP communications. They are typically used for short-term communication sessions when a client initiates a communication session with a server, after which the port is released for reuse. Dynamic ports range from 49152 to 65535 according to IANA (Internet Assigned Numbers Authority) standards. *For more information, view this lecture on [IP Addresses, MAC Addresses, and Port Numbers- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177398-ip-addresses-mac-addresses-and-port-numbers-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Ephemeral_port).*

Question 130

# Define: Eavesdropping

Answer 130

Unauthorized listening to or monitoring private conversations or data communication, posing a risk of confidential information leaks. ## Footnote A method where unauthorized individuals listen to, monitor, or intercept others' private conversations, data transmissions, or communications without consent. Eavesdropping can happen in various forms, such as wiretapping telephone lines, accessing email communications, or sniffing network packets. It's a primary concern in the world of communication and data transmission as it could lead to the leakage of confidential or sensitive information. *For more information, view this lecture on [The OSI Model- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177264-the-osi-model-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Eavesdropping).*

Question 131

# Define: Echo Checks

Answer 131

A method to verify the integrity of transmitted data by comparing a returned copy of the data with the original, used to detect errors in data communication. ## Footnote A simple error detection technique used in data communication to verify the integrity of transmitted data. In echo checks, a copy of the transmitted data is sent back to the sender for comparison with the original data. It's a common method for mitigating communication errors, ensuring that the data received at the other end is exactly what was sent, hence maintaining the reliability and integrity of data transmissions.

Question 132

# Define: Egress

Answer 132

Traffic exiting a network, particularly outbound data transfer, managed for security and compliance with network policies. ## Footnote In networking, egress refers specifically to traffic that is exiting a network. When data packets leave a network boundary en route to their destination, such as traffic departing from a private local area network (LAN) to the Internet, it is referred to as egress traffic. Egress control, including egress filtering and monitoring, is essential for network security to prevent unauthorized data transmission and ensure compliance with network policies. *For more information, view this lecture on [Network Performance and Traffic Management](https://courses.thorteaches.com/courses/take/cissp/lessons/54399148-new-2024-network-performance-and-traffic-management). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Egress_filtering).*

Question 133

# Define: Egress Filter

Answer 133

A network security measure to control and restrict outbound traffic, preventing data exfiltration and unauthorized communications. ## Footnote A network security measure that monitors and restricts the flow of outbound traffic from one network to another. Typically implemented in firewalls or routers, egress filtering rules ensure that only authorized data leaves the network, helping to prevent data exfiltration and stop the spread of malware. It's essential for enforcing network security policies and ensuring that only legitimate, necessary traffic is allowed out. *For more information, view this lecture on [Network Performance and Traffic Management](https://courses.thorteaches.com/courses/take/cissp/lessons/54399148-new-2024-network-performance-and-traffic-management). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Egress_filtering).*

Question 134

# Define: Egress Monitoring

Answer 134

Continuous oversight of data leaving a network to detect and prevent unauthorized data transfers and ensure information security. ## Footnote The process of continuously checking data leaving an organization's network for the purpose of detecting and preventing unauthorized data transfer. Through egress monitoring, organizations aim to protect sensitive information from leakage, theft, or misuse by insiders or compromised systems. This practice is a critical component of a comprehensive data loss prevention (DLP) strategy. *For more information, view this lecture on [Network Performance and Traffic Management](https://courses.thorteaches.com/courses/take/cissp/lessons/54399148-new-2024-network-performance-and-traffic-management). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Egress_filtering).*

Question 135

# Define: Email Gateway

Answer 135

A secure server that filters, scans, and routes email traffic for an organization. ## Footnote An email gateway serves as a critical checkpoint between external email sources and an organization’s internal network. It applies filtering rules, antivirus scanning, and spam detection to incoming and outgoing messages. By monitoring and managing email traffic, the gateway protects against malicious content, enforces compliance with policies, and ensures secure, efficient communication across the enterprise.

Question 136

# Define: Encapsulating Security Payload | (ESP)

Answer 136

A protocol providing security for internet communications, part of the IPSec suite for confidentiality and integrity. ## Footnote A component of the Internet Protocol Security (IPSec) suite used for ensuring secure communication by providing confidentiality, data origin authentication, connectionless integrity, and anti-replay. ESP achieves this by encapsulating the data to be protected, thus hiding the original data and safeguarding the integrity of the transmitted data. *For more information, view this lecture on [IPSec and PGP.](https://courses.thorteaches.com/courses/take/cissp/lessons/19149746-ipsec-and-pgp). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Encapsulating_Security_Payload).*

Question 137

# Define: Encapsulation

Answer 137

The process of wrapping data with protocol information for network transmission, also a data hiding concept in object-oriented programming. ## Footnote In computer networking, encapsulation refers to the process of wrapping data with necessary protocol information before network transmission. Similar to an envelope for a letter, it involves adding headers (and sometimes trailers) around data for proper delivery and processing. In object-oriented programming, encapsulation is a fundamental concept that binds together the data and functions that manipulate the data and keeps both safe from outside interference and misuse. Data encapsulation led to the important OOP concept of data hiding. *For more information, view this lecture on [The TCP-IP Model](https://courses.thorteaches.com/courses/take/cissp/lessons/19177306-the-tcp-ip-model). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Encapsulation_(networking)).*

Question 138

# Define: End-To-End Encryption

Answer 138

A communication method securing data so only the communicating users can access the messages, preventing third-party access. ## Footnote A method of secure communication that prevents third-parties from accessing data while it's transferred from one end system to another. In this system, data is encrypted on the sender's system or device, and only the recipient is able to decrypt it. No intermediary, including internet service providers, application service providers, and hackers, can read it or tamper with it. End-to-end encryption is widely used in messaging services, email communication, and secure file sharing to ensure that only the communicating users can read the messages. *For more information, view this lecture on [The Encryption We Use Today](https://courses.thorteaches.com/courses/take/cissp/lessons/19215118-the-encryption-we-use-today). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/End-to-end_encryption).*

Question 139

# Define: Ethernet

Answer 139

A widely-used networking technology for LANs, MANs, and WANs, facilitating reliable data packet exchange via physical cables and switches. ## Footnote A family of computer networking technologies commonly used in local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). Developed originally by Xerox in the 1970s and standardized by IEEE as IEEE 802.3, Ethernet has evolved to include various data rate standards and now serves as the backbone for most wired data networks. It uses both physical cables and switches to enable devices to communicate, offering a reliable and standardized way for computers, printers, and other network devices to exchange data packets. *For more information, view this lecture on [Networking Basics and Definitions](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Ethernet).*

Question 140

# Define: Evil Twin

Answer 140

A rogue wireless access point disguised as legitimate, used by attackers to intercept and manipulate users' network traffic. ## Footnote A rogue Wi-Fi access point that appears legitimate to users but is actually set up by an attacker to intercept wireless communications. The evil twin may mimic the name and settings of a legitimate access point to trick users into connecting to it, allowing the attacker to eavesdrop or manipulate their network traffic. *For more information, view this lecture on [WiFi - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178193-wifi-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Evil_twin_(wireless_networks)).*

Question 141

# Define: Exploitable Channel

Answer 141

A means through which vulnerabilities can be exploited to compromise systems or networks, such as software bugs or weak protocols. ## Footnote An exploitable channel is a term that generally refers to any means through which an attacker can exploit vulnerabilities to compromise a system or network. It can include software bugs, configuration weaknesses, or insecure network protocols. Identifying and securing these channels is crucial to protecting systems from potential breaches.

Question 142

# Define: Extended User Interface | (NetBEUI)

Answer 142

A non-routable networking protocol, once used for small LANs, now mostly obsolete due to TCP/IP prevalence. ## Footnote NetBEUI (NetBIOS Extended User Interface) is a non-routable networking protocol best suited for small to medium-sized local area networks. It's known for being simple to configure and efficient in LAN environments due to its lack of scalability features necessary for larger, segmented networks. Its name is derived from NetBIOS, a program that allows applications for different computers to communicate over a local area network. However, with the evolution of networking infrastructure and the dominance of TCP/IP, NetBEUI has become largely obsolete and is rarely used in modern network designs. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/NetBIOS#History_and_terminology).*

Question 143

# Define: External Border Gateway Protocol | (EBGP)

Answer 143

A BGP variant used for routing data between different networks, essential for Internet operability. ## Footnote A variant of the Border Gateway Protocol (BGP) used for routing data between autonomous systems (AS) on the Internet. EBGP enables separate and distinct networks, each managed by a different organization (such as an internet service provider or a large enterprise), to exchange routing information. This protocol ensures that networks can communicate and determine the best paths for data packets to travel across the complex fabric of the global Internet. EBGP plays a crucial role in the scalability and operation of the Internet by handling routing between different organizations efficiently and dynamically. *For more information, view this lecture on [Layer 1 to 3 networking devices.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178219-layer-1-to-3-networking-devices). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Border_Gateway_Protocol).*

Question 144

# Define: External Router

Answer 144

A device facilitating data transfer between different networks, managing and directing cross-network traffic. ## Footnote A device that connects networks together and facilitates data transfer between them. Primarily used for connecting to networks outside an organization's primary network, it serves as a gateway for data packets traveling between these disparate networks, controlling and directing traffic based on routing tables and protocols. *For more information, view this lecture on [Layer 1 to 3 networking devices.](https://courses.thorteaches.com/courses/take/cissp/lessons/19178219-layer-1-to-3-networking-devices).*

Question 145

# Define: Extranet

Answer 145

A private network using internet tech to securely share a business's operations or info with specific partners. ## Footnote A private network that uses internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses. It can be viewed as part of a company's intranet that is extended to users outside the company, offering controlled access while maintaining privacy and security. *For more information, view this lecture on [Networking basics and definitions.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Extranet).*

Question 146

# Define: Fault-Resistant Network

Answer 146

A network designed with redundancies and self-healing mechanisms to ensure continuous operation despite component failures. ## Footnote A fault-resistant network, often synonymous with fault-tolerant networking, incorporates design principles and technologies aimed at achieving continuous network operations despite failures of individual components. Such networks utilize redundancy, diverse routing paths, and self-healing mechanisms to prevent single points of failure and ensure service availability. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fault_tolerance).*

Question 147

# Define: FCIP | (Fiber Channel Over IP)

Answer 147

A protocol that encapsulates Fiber Channel frames for transmission over IP networks. ## Footnote FCIP is a technology that extends Fiber Channel storage networks over IP infrastructures by encapsulating Fiber Channel frames into IP packets. This method enables organizations to bridge geographic distances between storage areas without compromising data integrity or performance. FCIP thereby unifies storage area network (SAN) connectivity across disparate locations, facilitating centralized data management and enhanced scalability. *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fibre_Channel_over_IP).*

Question 148

# Define: FCoE | (Fiber Channel Over Ethernet)

Answer 148

A protocol that encapsulates Fiber Channel frames over Ethernet, enabling high-speed network and storage consolidation. ## Footnote A protocol that allows Fiber Channel communications to run directly over high-speed Ethernet networks, combining the robust and established world of Fiber Channel with the versatility and ubiquity of Ethernet. This provides a unified fabric that carries both storage and network traffic, thus simplifying data center infrastructure and reducing costs. *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fibre_Channel_over_Ethernet).*

Question 149

# Define: FHSS | (Frequency Hopping Spread Spectrum)

Answer 149

A communication method that rapidly switches frequencies to reduce interference and enhance security. ## Footnote A method of transmitting radio signals by shifting a carrier across numerous frequency channels in a pseudorandom sequence, known as the hopping pattern. This technique is used to avoid interference, prevent eavesdropping, and enable code-division multiple access (CDMA) communications. The recipient must be aware of the exact sequence to successfully receive the signal. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frequency-hopping_spread_spectrum).*

Question 150

# Define: Fiber Channel

Answer 150

A high-speed data transfer protocol commonly used in storage networking, especially within data centers for SANs. ## Footnote A high-speed network technology primarily used for storage networking. It's often used in data centers to connect servers to shared storage devices and for interconnecting storage controllers and drives. The technology provides one of the fastest transport mediums available for the SCSI protocol, which is widely used for storage area networks (SANs). *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fibre_Channel).*

Question 151

# Define: Fiber Channel Over Ethernet | (FCoE)

Answer 151

A protocol that allows Fiber Channel to use Ethernet networks, combining the strengths of both technologies. ## Footnote Fiber Channel over Ethernet (FCoE) is a storage networking protocol that encapsulates Fiber Channel frames over Ethernet networks. This convergence allows for the consolidation of network and storage infrastructure in data centers, reducing complexity and costs. FCoE operates on Ethernet networks that support a lossless transmission environment, necessary for handling Fiber Channel traffic. *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fibre_Channel_over_Ethernet).*

Question 152

# Define: Fiber Distributed Data Interface | (FDDI)

Answer 152

A now obsolete networking standard that used fiber optic lines in a LAN for high-speed data transfer. ## Footnote Fiber Distributed Data Interface (FDDI) is a set of ISO and ANSI standards for data transmission on fiber optic lines in a local area network (LAN). However, FDDI technology is considered obsolete and has been largely replaced by Ethernet and other faster networking standards that support higher bandwidths and longer distances with more cost-effectiveness. *For more information, view this lecture on [LAN topologies.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177530-lan-topologies). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fiber_Distributed_Data_Interface).*

Question 153

# Define: Fiber Optic Cable

Answer 153

Cables that use light to transmit data at high speeds over long distances, offering higher bandwidth and lower interference. ## Footnote A cable containing one or more optical fibers that are used to transmit data. Fiber optic cables have a core made from glass or plastic fibers that carry light to transmit data, enabling high-speed data transmission over longer distances with higher bandwidths than electrical cables. They are less susceptible to electromagnetic interference and signal loss, making them ideal for network backbones, telecommunications, and high-speed data connections in various environments. *For more information, view this lecture on [Cable types.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177465-cable-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Optical_fiber_cable).*

Question 154

# Define: File Server

Answer 154

A centralized network server for storing and managing files, controlling shared access, and ensuring data integrity and security. ## Footnote A server within a network that provides a centralized location for shared file storage, allowing users connected to the network to access and store files. It manages and controls file access to enhance security and ensure data integrity. File servers are commonly used in organizational environments to facilitate collaboration and data management. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/File_server).*

Question 155

# Define: File Transfer Protocol | (FTP)

Answer 155

A standard network protocol for file exchange between a client and server, lacking secure transfer features. ## Footnote A standard network protocol used for the transfer of computer files between a client and server on a computer network. FTP is built on a client-server model architecture using separate control and data connections between the client and the server. It allows users to upload, delete, access, and transfer files easily. Despite its widespread use, FTP lacks secure transfer features, which have led to the development and adoption of more secure transfer protocols like SFTP and FTPS. *For more information, view this lecture on [IP support protocols - Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/File_Transfer_Protocol).*

Question 156

# Define: File Transfer Protocol Secure | (FTPS)

Answer 156

An extension of FTP that adds support for secure communication protocols like TLS and SSL. ## Footnote An extension of the File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and the Secure Sockets Layer (SSL) cryptographic protocols. FTPS should not be confused with SFTP, which is an FTP-like protocol that is part of the SSH protocol suite. FTPS provides secure communication for file transfers by enabling encryption of the data transmitted, which helps prevent interception or eavesdropping. It is utilized to protect the transmission of data over insecure networks, such as the Internet, particularly when transferring sensitive or confidential information. *For more information, view this lecture on [IP support protocols - Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/FTPS).*

Question 157

# Define: FIN | (Final)

Answer 157

A TCP flag indicating that a session should end, part of the process to close network connections in an orderly fashion. ## Footnote In the context of network communications, "FIN" refers to a flag that is used in the TCP (Transmission Control Protocol) to indicate that a particular communication session has ended or should be closed. When a FIN flag is sent from one device to another, it means that the device sending the FIN flag has no more data to transmit. This flag is a crucial part of maintaining and closing network connections in an orderly manner. *For more information, view this lecture on [The OSI model- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/22712043-the-osi-model-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Transmission_Control_Protocol).*

Question 158

# Define: Firewall

Answer 158

A device that monitors and regulates network traffic based on security rules to protect against unauthorized access. ## Footnote A network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted internal network and an untrusted external network, such as the Internet. Firewalls are designed to prevent unauthorized access to or from private networks and can come in the form of hardware, software, or a combination of both. They are a fundamental part of network security and can perform various functions, including packet filtering, stateful inspection, proxy service, and network address translation (NAT). *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Firewall_(computing)).*

Question 159

# Define: Firewall as a Service | (FWaaS)

Answer 159

A service providing firewall and network security capabilities from the cloud, enhancing flexibility and reducing costs. ## Footnote A cloud-based solution that delivers firewall and other network security capabilities as a cloud service. It enables organizations to simplify their network security management by moving their security perimeter to the cloud, which can offer more flexibility, scalability, and cost-effectiveness compared to traditional on-premises firewall hardware. FWaaS typically includes features like intrusion prevention, URL filtering, and malware protection, and it is designed to protect both on-site and remote users in an increasingly decentralized IT landscape.

Question 160

# Define: Firewall Policy

Answer 160

A set of rules governing how a firewall manages network traffic, crucial for maintaining network security. ## Footnote A set of instructions or rules that dictate how a firewall should handle inbound or outbound network traffic. The policy is often based on IP addresses, domain names, protocols, programs, ports, or specific network interfaces. The policies dictate which types of traffic are permitted and which are not, enhancing security by blocking potentially harmful traffic or specific services that should not be publicly available. *For more information, view this lecture on [Firewalls Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178275-firewalls-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Firewall_(computing)#Firewall_Policies).*

Question 161

# Define: Flooding

Answer 161

A security attack that overwhelms a system with excessive traffic, leading to disruptions or complete failure. ## Footnote A type of security attack where the network or system is overwhelmed with traffic or data, resulting in overconsumption of available resources. It could lead to system slowdowns or, in extreme cases, cause the system to crash entirely. Common types of flooding include Distributed Denial of Service (DDoS) attacks, where an attacker inundates a network with unwanted traffic, often from a botnet. *For more information, view this lecture on [Firewalls Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/33182521-firewalls-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Flooding_(computer_networking)).*

Question 162

# Define: Forwarding Plane

Answer 162

The component of a network device responsible for transmitting data packets to their destination. ## Footnote The Forwarding Plane, also known as the data plane, is the part of a network device that handles the actual movement of data packets based on established routing or switching tables. It operates under the guidance of the control plane, processing packets at high speeds to ensure efficient data delivery. The performance and reliability of the forwarding plane are critical in maintaining low-latency and high-throughput network operations. *For more information, view this lecture on [SAN and VoIP protocols.](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Data_plane).*

Question 163

# Define: Fraggle Attack

Answer 163

A DoS attack that floods a network with spoofed UDP traffic to multiple devices, amplifying the attack's impact. ## Footnote A Fraggle attack is a type of denial of service (DoS) attack that targets a network by sending a large amount of spoofed UDP traffic to the network's broadcast address. Each packet prompts devices to respond, creating a flood of traffic that can overload and disrupt services. This exploit takes advantage of the amplification effect of broadcasting to multiple devices, thereby magnifying the attack's impact. *For more information, view this lecture on [The OSI Model- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/22712043-the-osi-model-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Smurf_attack#Fraggle_Attack).*

Question 164

# Define: Frame Relay

Answer 164

A network technology for efficient data transmission across LANs and WANs, requiring security measures like data encryption. ## Footnote A high-speed, packet-switched telecommunications network technology that was designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints in a wide area network (WAN). Because of its nature, it's crucial to implement proper security measures, like encrypting data before transmission, to protect data integrity and prevent unauthorized access. *For more information, view this lecture on [WAN Protocols](https://courses.thorteaches.com/courses/take/cissp/lessons/19177534-wan-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frame_Relay).*

Question 165

# Define: Frequency

Answer 165

The rate at which a repetitive event occurs over time, often key to determining data transmission rates in communication. ## Footnote The number of occurrences of a repeating event per unit of time. It is most often associated with waves, like radio waves, and determines the data transmission rate. High-frequency waves can transmit more data but may also be more susceptible to interception or interference, leading to potential data loss or unauthorized access. *For more information, view this lecture on [WiFi - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178193-wifi-part-1). Or view this lecture on [WiFi - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/29948642-wifi-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frequency).*

Question 166

# Define: Frequency Division Multiplexing | (FDM)

Answer 166

A communication technique allowing multiple signals to share a single channel by assigning them different frequency bands. ## Footnote A communication scheme that allows numerous signals to share a single transmission channel by splitting the total bandwidth available into a series of non-overlapping frequency bands, each of which is used to carry a separate signal. This technique can enhance the efficiency of a network but also presents unique security concerns. Unauthorized users could potentially tap into the shared transmission channel and intercept sensitive information. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frequency-division_multiplexing).*

Question 167

# Define: Frequency Hopping

Answer 167

A method of transmitting signals by rapidly switching frequencies to minimize eavesdropping and interference. ## Footnote A method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. This technique minimizes the risk of interference and interception, as it appears as short bursts of noise on any one channel. It is widely used in technologies like Bluetooth and some secure communication channels. Frequency hopping is effective against signal jamming and eavesdropping and improves the sharing of the radio spectrum among multiple users. *For more information, view this lecture on [WiFi - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19178193-wifi-part-1). Or view this lecture on [WiFi - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/29948642-wifi-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frequency-hopping_spread_spectrum).*

Question 168

# Define: Frequency-Division Multiplexing | (FDM)

Answer 168

A technique for transmitting multiple signals simultaneously over a single communication channel by dividing bandwidth. ## Footnote A technique used in the telecommunications field that allows multiple signals to be transmitted simultaneously over a single communication line or medium by allocating a unique frequency range to each signal. This separation of the total bandwidth into various non-overlapping frequency sub-bands reduces interference and enhances communication reliability. FDM finds wide usage in radio and TV broadcasting, satellite and cable systems, as well as telephone networks. *Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Frequency-division_multiplexing).*

Question 169

# Define: Full-Duplex Mode

Answer 169

A communication method allowing simultaneous data transmission and reception, like a telephone conversation. ## Footnote A type of communication where data transmission can occur in both directions simultaneously. This means that devices can send and receive signals at the same time, similar to a telephone conversation where both parties can talk and listen simultaneously. Full-duplex systems, therefore, double the capacity of a communication channel, as data does not need to be sent in a singular direction at a time, unlike half-duplex systems where communication can only go one way at any given moment. Full-duplex mode is commonly used in various telecommunications and computing scenarios to improve the efficiency of communication channels. *For more information, view this lecture on [Networking Basics and Definitions](https://courses.thorteaches.com/courses/take/cissp/lessons/19177258-networking-basics-and-definitions). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Duplex_(telecommunications)).*

Question 170

# Define: Gateway

Answer 170

A network node that serves as an access point to another network, translating data for communication between different protocols. ## Footnote A node in a network that serves as an access point to another network, often enabling networks using different protocols to communicate with each other. It essentially acts as a mediator, translating data between different networking protocols to ensure smooth data transfer. In security, gateways often include functions like firewalls, intrusion detection systems, or filtering to protect against potential threats and maintain the integrity and security of data passing through. *For more information, view this lecture on [IP Support Protocols - Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19177457-ip-support-protocols-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Gateway_(telecommunications)).*