A-L Flashcards
IT Support Certificate glossary A-L
404 Not Found:
404 Not Found: An error message you might see on websites that have been moved or deleted
802.1X:
802.1X: It is the IEEE standard for encapsulating EAP or Extensible Authentication Protocol traffic over the 802 networks
802.1X with EAP-TLS:
802.1X with EAP-TLS: Offers arguably the best security available, assuming proper and secure handling of the PKI aspects of it
AAA (authentication, authorization, accounting):
AAA (authentication, authorization, accounting): The services that the directory services provide to all the computers within a company or organization
Abstraction:
Abstraction: To take a relatively complex system and simplify it for our use
Absolute path:
Absolute path: It is one that starts from the main directory
Access Control Entries:
Access Control Entries: The individual access permissions per object that make up the ACL
Access Control List (ACL):
Access Control List (ACL): It is a way of defining permissions or authorizations for objects
Accounting:
Accounting: Keeping records of what resources and services your users access or what they did when they were using your systems
ACI:
ACI: Access Control Lists
ACK flag:
ACK flag: One of the TCP control flags. ACK is short for acknowledge. A value of one in this field means that the acknowledgment number field should be examined
Acknowledgement number:
Acknowledgement number: The number of the next expected segment in a TCP sequence
Activation threshold:
Activation threshold: Triggers a pre-configured action when it is reached and will typically block the identified attack traffic for a specific amount of time
Active directory (AD):
Active directory (AD): The Microsoft alternative to directory services that offers customization and added features for the Windows platform
Active directory users and computers (ADUC):
Active directory users and computers (ADUC): The client tools that are used for accessing and administering a directory server
Address bus:
Address bus: Connects the CPU to the MCC and sends over the location of the data, but not the data itself
Address class system:
Address class system: A system which defines how the global IP address space is split up
Address Resolution Protocol (ARP):
Address Resolution Protocol (ARP): A protocol used to discover the hardware address of a node with a certain IP address
Ad-Hoc network:
Ad-Hoc network: A network configuration without supporting network infrastructure. Every device involved with the ad-hoc network communicates with every other device within range, and all nodes help pass along messages
Administrator:
Administrator: A user that has complete control over a machine
Advanced Encryption Standard (AES):
Advanced Encryption Standard (AES): The first and only public cipher that’s approved for use with top secret information by the United States National Security Agency
Advanced group policy management (AGPM):
Advanced group policy management (AGPM): A set of add-on tools from Microsoft that gives some added provision control abilities in GPMC
Adware:
Adware: Software that displays advertisements and collects data
Algorithm:
Algorithm: A series of steps that solves specific problems
Alias:
Alias: A nickname for common commands
Analyzing logs:
Analyzing logs: The practice of collecting logs from different network and sometimes client devices on your network, then performing an automated analysis on them
Android
Android: A mobile operating system based on Linux
Antivirus software:
Antivirus software: It monitors and analyze things like new files being created or being modified on the system in order to watch for any behavior that matches a known malware signature
Anycast:
Anycast: A technique that’s used to route traffic to different destinations depending on factors like location, congestion, or link health
Appending flags:
Appending flags: A way to add the data of the file without erasing existing data
Application:
Application: A computer program designed for a specific use
Application layer:
Application layer: The layer that allows network applications to communicate in a way they understand
Application layer payload:
Application layer payload: The entire contents of whatever data applications want to send to each other
Application policies:
Application policies: Defines boundaries of what applications are permitted or not, but they also help educate folks on how to use software more securely
Application software:
Application software: Any software created to fulfill a specific need, like a text editor, web browser, or graphics editor
App store apps:
App store apps: A Package Manager that acts as a repository
App store repository:
App store repository: A app store service that also acts as a repository
App stores:
App stores: A central managed marketplace for app developers to publish and sell mobile apps
APPX:
APPX: An APPX is another way to package contents of a file to act like a unit of distribution
Archive:
Archive: An archive is comprised of one or more files that are compressed into a single file” for verb agreement
A record:
A record: The most common resource record, used to point a certain domain name at a certain IPv4 IP address
ARPANET:
ARPANET: The earliest version of the Internet that we see today, created by the US government project DARPA in the 1960s
ARP table:
ARP table: A list of IP addresses and the MAC addresses associated with them
ASCII:
ASCII: The oldest character encoding standard used is ASCII. It represents the English alphabet, digits, and punctuation marks
ASN:
ASN: Autonomous System Number is a number assigned to an individual autonomous system
Assembly language:
Assembly language: A language that allowed computer scientists to use human readable instructions, assembled into code that the machines could understand
Asymmetric Digital Subscriber Line (ADSL):
Asymmetric Digital Subscriber Line (ADSL): A device that establishes data connections across phone lines and different speeds for uploading and downloading data
Asymmetric encryption:
Asymmetric encryption: Systems where different keys are used to encrypt and decrypt
ATA:
ATA: The most common interface that hard drives use to connect to our system
Attack:
Attack: An actual attempt at causing harm to a system
Attack surface:
Attack surface: It’s the sum of all the different attack vectors in a given system
Attack vector:
Attack vector: Method or mechanism by which an attacker or malware gains access to a network or system
ATX (Advanced Technology eXtended):
ATX (Advanced Technology eXtended): The most common form factor for motherboards
Auditing:
Auditing: It involves reviewing records to ensure that nothing is out of the ordinary
Authentication:
Authentication: A crucial application for cryptographic hash functions
Authentication server (AS):
Authentication server (AS): It includes the user ID of the authenticating user
Authorization:
Authorization: It pertains to describing what the user account has access to or doesn’t have access to
Automatic allocation:
Automatic allocation: A range of IP addresses is set aside for assignment purposes
Automation:
Automation: It makes processes work automatically
Autoscaling:
Autoscaling: A system that allows the service to increase or reduce capacity as needed, while the service owner only pays for the cost of the machines that are in use at any given time
Availability:
Availability: Means that the information we have is readily accessible to those people that should have it
Backdoor:
Backdoor: A way to get into a system if the other methods to get in a system aren’t allowed, it’s a secret entryway for attackers
Background processes/Daemon processes:
Background processes/Daemon processes: Processes that run or take place in the background
Backup and restore:
Backup and restore: A Microsoft offer and first party solution that has modes of operation, as a file based version where files are backed up to a zip archive
Backward compatible:
Backward compatible: It means older hardware works with newer hardware
Baiting:
Baiting: An attack that happens through actual physical contact, enticing a victim to do something
Bash:
Bash: The language used to interact with the shell
Bastion hosts or networks:
Bastion hosts or networks: A server used to provide access to a private network from an external network
Baud rate:
Baud rate: A measurement of how many bits could be passed across a phone line in a second
Binary system:
Binary system: The communication that a computer uses is referred to as binary system, also known as base-2 numeral system
Binary whitelisting software:
Binary whitelisting software: It’s a list of known good and trusted software and only things that are on the list are permitted to run
Bind:
Bind: It is how clients authenticate to the server
Bind operation:
Bind operation: The operation which authenticates clients to the directory server
Biometric authentication:
Biometric authentication: Authentication that uses Biometric data
Biometric data:
Biometric data: A way of protecting your accounts and information using biometric data such as facial recognition and fingerprint
BIOS/UEFI:
BIOS/UEFI: A low-level software that initializes our computer’s hardware to make sure everything is good to go
Bios (Basic Input Output Services):
Bios (Basic Input Output Services): The BIOS is software that helps initialize the hardware in our computer and gets our operating system up and running
Bit:
Bit: The smallest representation of data that a computer can understand
Block ciphers:
Block ciphers: The cipher takes data in, places that into a bucket or block of data that’s a fixed size, then encodes that entire block as one unit
Block devices:
Block devices: A system that acts like USB drives and hard drive by transmitting data
Block storage:
Block storage: It improves faster handling of data because the data isn’t stored in one long piece but in blocks, so it can be accessed more quickly
Bluetooth:
Bluetooth: The most common short range wireless network
Boot:
Boot: To start up a computer
Bootloader:
Bootloader: A small program that loads the operating system
Border Gateway Protocol (BGP):
Border Gateway Protocol (BGP): A protocol by which routers share data with each other
Botnet:
Botnet: A collection of one or more Bots
Bots:
Bots: Machines compromised by malware that are utilized to perform tasks centrally controlled by an attacker
Broadband:
Broadband: Any connectivity technology that isn’t dial-up Internet
Broadcast:
Broadcast: A type of Ethernet transmission, sent to every single device on a LAN
Broadcast address:
Broadcast address: A special destination used by an Ethernet broadcast composed by all Fs
Browser:
Browser: A user interface for displaying and interacting with web pages
Brute force attacks:
Brute force attacks: A common password attack which consists of just continuously trying different combinations of characters and letters until one gets access
BYOD (Bring Your Own Device):
BYOD (Bring Your Own Device): Refers to the practice of allowing people to use their own personal devices for work
Byte:
Byte: A group of 8 bits
CA (Certificate authority):
CA (Certificate authority): It’s the entity that’s responsible for storing, issuing, and signing certificates. It’s a crucial component of the PKI system
Cable categories:
Cable categories: Groups of cables that are made with the same material. Most network cables used today can be split into two categories, copper and fiber
Cable modem:
Cable modem: A device that sits at the edge of a consumer’s network and connects it to the cable modem termination system
Cable modem termination system:
Cable modem termination system: Connects lots of different cable connections to an ISP’s core network
Cables:
Cables: Insulated wires that connect different devices to each other allowing data to be transmitted over them
Cache:
Cache: The assigned stored location for recently or frequently accessed data; on a mobile app it is where anything that was changed or created with that app is stored
Cache:
Cache: The assigned stored location for recently or frequently accessed data; on a mobile app it is where anything that was changed or created with that app is stored
Caching and recursive name servers:
Caching and recursive name servers: They are generally provided by an ISP or your local network, and their purpose is to store domain name lookups for a certain amount of time
Caesar cipher:
Caesar cipher: A substitution alphabet, where you replace characters in the alphabet with others usually by shifting or rotating the alphabet, a set of numbers or characters
Carrier-Sense Multiple Access with Collision Detection (CSMA/CD):
Carrier-Sense Multiple Access with Collision Detection (CSMA/CD): CSMA/CD is used to determine when the communications channels are clear and when the device is free to transmit data
CBC-MAC (Cipher block chaining message authentication codes):
CBC-MAC (Cipher block chaining message authentication codes): A mechanism for building MACs using block ciphers
CCMP (counter mode CBC-MAC protocol):
CCMP (counter mode CBC-MAC protocol): A mode of operation for block ciphers that allows for authenticated encryption
Centralized logging:
Centralized logging: Parsing logs in one central location
Central management:
Central management: A central service that provides instructions to all of the different parts of my IT infrastructure
Central repository:
Central repository: It is needed to securely store and index keys and a certificate management system of some sort makes managing access to storage certificates and issuance of certificates easier
Certificate-based authentication:
Certificate-based authentication: It is the most secure option, but it requires more support and management overhead since every client must have a certificate
Certificate fingerprints:
Certificate fingerprints: These are just hash digests of the whole certificate, and aren’t actually fields in the certificate itself, but are computed by clients when validating or inspecting certificates
Certificate Revocation List (CRL):
Certificate Revocation List (CRL): A means to distribute a list of certificates that are no longer valid
Certificate Signature Algorithm:
Certificate Signature Algorithm: This field indicates what public key algorithm is used for the public key and what hashing algorithm is used to sign the certificate
Certificate Signature Value:
Certificate Signature Value: The digital signature data itself
Change management process:
Change management process: The process to notify others in the organization about the changes that you are about to make
Channels:
Channels: Individual, smaller sections of the overall frequency band used by a wireless network
Character devices:
Character devices: A way to transmit data character by character like a keyboard and mouse
Character encoding:
Character encoding: Is used to assign our binary values to characters so that we as humans can read them
Charge cycle:
Charge cycle: One full charge and discharge of a battery
Child directories:
Child directories: It is a directory housed by a parent directory
Children’s Online Privacy Protection Act (COPPA):
Children’s Online Privacy Protection Act (COPPA): Regulates the information we show to children under the age of 13
Chipset:
Chipset: It decides how components talk to each other on our machine
Chocolatey:
Chocolatey: A third party package manager for Windows
Chrome OS:
Chrome OS: A Linux-based operating system designed by Google
CIA Triad:
CIA Triad: Confidentiality, integrity, and availability. Three key principles of a guiding model for designing information security policies
CLI:
CLI: Command line interpreter
Client:
Client: A device that receives data from a server
Client/Server runtime subsystem:
Client/Server runtime subsystem: System that handles running Windows GUI and Command line
Client certificates:
Client certificates: They operate very similarly to server certificates but are presented by clients and allow servers to authenticate and verify clients
Clients:
Clients: A device that receives data from a server
Clock cycle:
Clock cycle: When you send a voltage to the clock wire
Clock speed:
Clock speed: The maximum number of clock cycles that it can handle in a set in a certain time period
Clock wire:
Clock wire: When you send or receive data, it sends a voltage to that clock wire to let the CPU know it can start doing calculations
CLOSE_WAIT:
CLOSE_WAIT: A connection state that indicates that the connection has been closed at the TCP layer, but that the application that opened the socket hasn’t released its hold on the socket yet
CLOSE:
CLOSE: A connection state that indicates that the connection has been fully terminated, and that no further communication is possible
Closed source packages:
Closed source packages: A source code that does not allow public access
Cloud computing
Cloud computing: The concept and technological approach of accessing data, using applications, storing files, etc. from anywhere in the world as long as you have an internet connection
CMACs (Cipher-based Message Authentication Codes):
CMACs (Cipher-based Message Authentication Codes): The process is similar to HMAC, but instead of using a hashing function to produce a digest, a symmetric cipher with a shared keys used to encrypt the message and the resulting output is used as the MAC
CNAME:
CNAME: A resource record used to map one domain to another
Code signing certificates:
Code signing certificates: It is used for signing executable programs and allows users of these signed applications to verify the signatures and ensure that the application was not tampered with
Coding:
Coding: Translating one language to another
Collision domain:
Collision domain: A network segment where only one device can communicate at a time
Command line:
Command line: A text interface program for a computer that inputs text commands and translates them to the operating system
Command Line Interface (CLI):
Command Line Interface (CLI): A shell that uses text commands to interact with the operating system
Command line mode:
Command line mode: When you are able to run commands while still in your current shell
Compiled programming language:
Compiled programming language: A language that uses human readable instructions, then sends them through a compiler
Computer:
Computer: A device that stores and processes data by performing calculations
Computer configuration:
Computer configuration: Contained within a Group Policy Object (GPO)
Computer file:
Computer file: Data that we store and a file can be anything, a word document, a picture, a song, literally anything
Computer management:
Computer management: A tool that lets you manage a local or remote computer
Computer networking:
Computer networking: The full scope of how computers communicate with each other
Confidentiality:
Confidentiality: Keeping things hidden
Configuration management:
Configuration management: The creation of rules about how things should work in your organization, such as printers, configure software, or mounting network file systems
Connectionless protocol:
Connectionless protocol: A data-transmission protocol that allows data to be exchanged without an established connection at the transport layer. The most common of these is known as UDP, or User Datagram Protocol
Connection-oriented protocol:
Connection-oriented protocol: A data-transmission protocol that establishes a connection at the transport layer, and uses this to ensure that all data has been properly transmitted
Copper cable categories :
Copper cable categories : These categories have different physical characteristics like the number of twists in the pair of copper wires. These are defined as names like category (or cat) 5, 5e, or 6, and how quickly data can be sent across them and how resistant they are to outside interference are all related to the way the twisted pairs inside are arranged
Copyright:
Copyright: Used when creating original work
Correlation analysis:
Correlation analysis: The process of taking log data from different systems, and matching events across the systems
Counter-based tokens:
Counter-based tokens: They use a secret seed value along with the secret counter value that’s incremented every time a one-time password is generated on the device
CPU:
CPU: Central processing unit
CPU sockets:
CPU sockets: A CPU socket is a series of pins that connect a CPU?s processor to the PC?s motherboard
Cross-site scripting (XSS):
Cross-site scripting (XSS): A type of injection attack where the attacker can insert malicious code and target the user of the service
Crosstalk:
Crosstalk: Crosstalk is when an electrical pulse on one wire is accidentally detected on another wire
Cryptanalysis:
Cryptanalysis: Looking for hidden messages or trying to decipher coded message
Cryptographic hashing:
Cryptographic hashing: It is distinctly different from encryption because cryptographic hash functions should be one directional
Cryptography:
Cryptography: The overarching discipline that covers the practice of coding and hiding messages from third parties
Cryptography:
Cryptography: The overarching discipline that covers the practice of coding and hiding messages from third parties
Cryptology:
Cryptology: The study of cryptography
Cryptosystem:
Cryptosystem: A collection of algorithms for key generation and encryption and decryption operations that comprise a cryptographic service
Cyclical Redundancy Check (CRC):
Cyclical Redundancy Check (CRC): A mathematical transformation that uses polynomial division to create a number that represents a larger set of data. It is an important concept for data integrity and is used all over computing, not just network transmissions
DACL:
DACL: Directory Control Lists
DARPA:
DARPA: A US government project in the 1960s that went on to create the earliest version of the Internet that we see today
Data:
Data: Actual content of a file
Databases:
Databases: Databases allow us to store query, filter, and manage large amounts of data
Data binding and sealing:
Data binding and sealing: It involves using the secret key to derive a unique key that’s then used for encryption of data
Data blocks:
Data blocks: Data that can be broken down into many pieces and written to different parts of the hard disk
Data buffer:
Data buffer: A region of RAM that?s used to temporarily store data while it?s being moved around
Data center:
Data center: A facility that stores hundreds, if not thousands of servers
Data exfiltration
Data exfiltration: The unauthorized transfer of data from a computer. It’s also a very important concern when a security incident happens
Data handling policies:
Data handling policies: Should cover the details of how different data is classified
Data information tree:
Data information tree: A structure where objects will have one parent and can have one or more children that belong to the parent object
Datalink layer:
Datalink layer: The layer in which the first protocols are introduced. This layer is responsible for defining a common way of interpreting signals, so network devices can communicate
Data offset field:
Data offset field: The number of the next expected segment in a TCP packet/datagram
Data packet:
Data packet: An all-encompassing term that represents any single set of binary data being sent across a network link
Data payload section:
Data payload section: Has all of the data of the protocols further up the stack of a frame
Data recovery:
Data recovery: Is the process of trying to restore data after an unexpected event that results in data loss or corruption
Data sizes:
Data sizes: Metrics that refer to data sizes including bit, byte, kilobyte, kibibyte, and megabyte
Data tapes:
Data tapes: The standard medium for archival backup data storage
DDR SDRAM (Double Data Rate SDRAM):
DDR SDRAM (Double Data Rate SDRAM): A type of RAM that is faster, takes up less power, and has a larger capacity than earlier SDRAM versions
Debian(.deb):
Debian(.deb): A Debian package is packaged as a .deb file
Decimal form- base 10 system:
Decimal form- base 10 system: In the decimal system, there are 10 possible numbers you can use ranging from zero to nine
Decryption:
Decryption: The reverse process from encryption; taking the garbled output and transforming it back into the readable plain text
Default domain control policy:
Default domain control policy: One of the two GPOs that are created when a new Active Directory domain has been made
Defense in depth:
Defense in depth: The concept of having multiple overlapping systems of defense to protect IT systems
Defragmentation:
Defragmentation: A process of taking all the files stored on a given disk and reorganizing them into neighboring locations
Delegation:
Delegation: The administrative tasks that you need to perform a lot as a part of your day to day job but you don’t need to have broad access to make changes in AD
Demarcate:
Demarcate: To set the boundaries of something
Demarcation point:
Demarcation point: Where one network or system ends and another one begins
Demultiplexing:
Demultiplexing: Taking traffic that’s all aimed at the same node and delivering it to the proper receiving service
Denial-of-Service (DoS) attack:
Denial-of-Service (DoS) attack: An attack that tries to prevent access to a service for legitimate users by overwhelming the network or server
Deployment:
Deployment: Hardware is set up so that the employee can do their job
DES (Data Encryption Standard):
DES (Data Encryption Standard): One of the earliest encryption standards
Desktop:
Desktop: The main screen where we can navigate our files, folders, and applications
Destination MAC address
Destination MAC address: The hardware address of the intended recipient that immediately follows the start frame delimiter
Destination network:
Destination network: The column in a routing table that contains a row for each network that the router knows about
Destination port:
Destination port: The port of the service the TCP packet is intended for
Detection measure:
Detection measure: The measures to alert you and your team that a disaster has occurred that can impact operations
Deterministic:
Deterministic: It means that the same input value should always return the same hash value
Device manager:
Device manager: A console management system for your device
DH (Diffie-Hellman):
DH (Diffie-Hellman): A popular key exchange algorithm, named for its co-inventors
DHCP:
DHCP: A technology that assigns an IP address automatically to a new device. It is an application layer protocol that automates the configuration process of hosts on a network
DHCP discovery:
DHCP discovery: The process by which a client configured to use DHCP attempts to get network configuration information
Dial-up:
Dial-up: Uses POTS for data transfer, and gets its name because the connection is established by actually dialing a phone number
Dictionary attack:
Dictionary attack: A type of password attack that tries out words that are commonly used in passwords, like password, monkey, football
Differential backup:
Differential backup: A backup of files that are changed, or has been created since the last full backup
Digital divide:
Digital divide: The growing skills gap between people with and without digital literacy skills
DIMM:
DIMM: Dual Inline Memory Module
Directory Access Protocol (DAP):
Directory Access Protocol (DAP): A protocol that is included in the X.500 directory standard from 1988
Directory Information Shadow Protocol (DISP):
Directory Information Shadow Protocol (DISP): A protocol that is included in the X.500 directory standard from 1988
Directory Operational Bindings Protocol (DOBMP):
Directory Operational Bindings Protocol (DOBMP): A protocol that is included in the X.500 directory standard from 1988
Directory server:
Directory server: The server that contains a lookup service that provides mapping between network resources and their network addresses
Directory services:
Directory services: A lookup service contained in a network server that provides mapping between network resources and their network addresses
Directory System Protocol (DSP):
Directory System Protocol (DSP): A protocol that is included in the X.500 directory standard from 1988
Disaster recovery plan:
Disaster recovery plan: A collection of documented procedures and plans on how to react and handle an emergency or disaster scenario, from the operational perspective
Disaster recovery testing:
Disaster recovery testing: A regular exercise that happens once a year or so, that has different teams, including IT support specialists, going through simulations of disaster events
Disk Management utility:
Disk Management utility: Native tool for Windows that helps with managing disk space
Disk to disk cloning:
Disk to disk cloning: A type of cloning that happens when you connect an external hard drive to the machine you want to clone
Display port:
Display port: Port which also outputs audio and video
Distinguished name (DN):
Distinguished name (DN): A unique identifier for each entry in the directory
Distributed Denial-of-Service (DDoS) attack:
Distributed Denial-of-Service (DDoS) attack: A DoS attack using multiple systems
Distribution:
Distribution: A version of the operating system
Distribution group:
Distribution group: A group that is only designed to group accounts and contacts for email communication
Distributions:
Distributions: Some common Linux distributions are Ubuntu, Debian, and Red Hat
DNS Cache Poisoning Attack:
DNS Cache Poisoning Attack: It works by tricking a DNS server into accepting a fake DNS record that will point you to a compromised DNS server
DNS records:
DNS records: A DNS request for the SRV records matching the domain that it’s been bound to
DNS zones:
DNS zones: A portion of space in the Domain Name System (DNS) that is controlled by an authoritative name server
Domain:
Domain: Used to demarcate where control moves from a top-level domain name server to an authoritative name server
Domain admin:
Domain admin: The administrators of the Active Directory domain
Domain computers:
Domain computers: All the computers joined to the domain except domain controllers
Domain controllers (DC):
Domain controllers (DC): The service that hosts copies of the Active Directory database
Domain local:
Domain local: The tool used used to assign permission to a resource
Domain name:
Domain name: A website name; the part of the URL following www.
Domain Name System (DNS):
Domain Name System (DNS): A global and highly distributed network service that resolves strings of letters, such as a website name, into an IP address
Domain users:
Domain users: A group that contains every user account in the domain
Dotted decimal notation:
Dotted decimal notation: A format of using dots to separate numbers in a string, such as in an IP address
DRAM:
DRAM: Dynamic Random Access Memory
Driver:
Driver: Used to help our hardware devices interact with our Operating System
Drivers:
Drivers: The drivers contain the instructions our CPU needs to understand external devices like keyboards, webcams, printers
DSA (Digital Signature Algorithm):
DSA (Digital Signature Algorithm): It is another example of an asymmetric encryption system, though its used for signing and verifying data
DSL:
DSL: Digital subscriber line was able to send much more data across the wire than traditional dial-up technologies by operating at a frequency range that didn’t interfere with normal phone calls
DSLAM:
DSLAM: Digital Subscriber Line Access Multiplexers are devices that connect multiple DSL connections to a high-speed digital communications channel
Duplex communication:
Duplex communication: A form of communication where information can flow in both directions across a cable
Duration field:
Duration field: Specifies how long the total frame is
DVI:
DVI: DVI cables generally just output video
Dynamic allocation:
Dynamic allocation: A range of IP addresses is set aside for client devices and one of these IPs is issued to these devices when they request one
Dynamic ARP inspection (DAI):
Dynamic ARP inspection (DAI): A feature on enterprise switches that prevents certain types of attacks
Dynamic IP address:
Dynamic IP address: An IP address assigned automatically to a new device through a technology known as Dynamic Host Configuration Protocol
Dynamic-link libraries:
Dynamic-link libraries: Programs that want to use functionality that the code provides can tap into it if they need to (shared libraries)
.exe:
.exe: A file extension found in Windows for an executable file
EAP-TLS:
EAP-TLS: One of the more common and secure EAP methods
ECDH & ECDSA:
ECDH & ECDSA: Elliptic curve variants of Diffie-Hellman and DSA, respectively
Electrostatic discharge:
Electrostatic discharge: Electrostatic discharge is a sudden and momentary flow of electric current between two electrically charged objects caused by contact, an electrical short or dielectric breakdown
Eliptic curve cryptography (ECC):
Eliptic curve cryptography (ECC): A public key encryption system that uses the algebraic structure of elliptic curves over finite fields to generate secure keys
Encapsulating security payload:
Encapsulating security payload: It’s a part of the IPsec suite of protocols, which encapsulates IP packets, providing confidentiality, integrity, and authentication of the packets
Encryption:
Encryption: The act of taking a message (plaintext), and applying an operation to it (cipher), so that you receive a garbled, unreadable message as the output (ciphertext)
Encryption algorithm:
Encryption algorithm: The underlying logic or process that’s used to convert the plaintext into ciphertext
End-entity (leaf certificate):
End-entity (leaf certificate): A certificate that has no authority as a CA
Enterprise admin:
Enterprise admin: The administrators of the Active Directory domain that has permission to make changes to the domain that affect other domains in a multi-domain forest
Enterprise app management:
Enterprise app management: A management system that allows an organization to distribute custom mobile apps
Enterprise mobility management (EMM):
Enterprise mobility management (EMM): A system that can create and distribute policies and MDMs
Entropy pool:
Entropy pool: A source of random data to help seed random number generators
Entry point:
Entry point: the act to determine the entry point to figure out how the attacker got in, or what vulnerability the malware exploited
Environment:
Environment: Whatever settings or variables a child process inherits from the parent?s process
Error detection:
Error detection: The ability for a protocol or program to determine that something went wrong
Error message:
Error message: Helpful indicators that can point you in the right direction
Error recovery
Error recovery: The ability for a protocol or program to attempt to fix an error
Escape characters:
Escape characters: A concept that means that the next character after the back tick should be treated literally
ESTABLISHED:
ESTABLISHED: Status indicating that the TCP connection is in working order, and both sides are free to send each other data
Etcher.io:
Etcher.io: A tool you can use to load an install image onto your USB device and make it bootable
Ethernet:
Ethernet: The protocol most widely used to send data across individual links
Ethernet cable:
Ethernet cable: It lets you physically connect to the network through a cable
Ethernet frame:
Ethernet frame: A highly structured collection of information presented in a specific order
EtherType field:
EtherType field: It follows the Source MAC Address in a dataframe. It’s 16 bits long and used to describe the protocol of the contents of the frame
Event Viewer:
Event Viewer: A place where all events that have been logged are stored
Evil twin:
Evil twin: The premise of an evil twin attack is for you to connect to a network that is identical to yours but that is controlled by an attacker. Once connected to it, they will be able to monitor your traffic
Executable file:
Executable file: A file containing instructions for a computer to execute when they?re run
Expansion slots:
Expansion slots: Give us the ability to increase the functionality of our computer
Exploit:
Exploit: Software that is used to take advantage of a security bug or vulnerability
Extensible authentication protocol (EAP over LAN, or EAPOL):
Extensible authentication protocol (EAP over LAN, or EAPOL): A standard authentication protocol
Exterior gateway:
Exterior gateway: Protocols that are used for the exchange of information between independent autonomous systems
External Data Bus (EDB):
External Data Bus (EDB): It’s a row of wires that interconnect the parts of our computer
Factory reset:
Factory reset: Resetting a device to the settings it came with from the factory
Fail to ban:
Fail to ban: A common open source flood guard protection tool
Fast logon optimization:
Fast logon optimization: The group policy engine that applies policy settings to a local machine may sacrifice the immediate application of some types of policies in order to make logon faster
Fiber optic cable:
Fiber optic cable: Fiber optic cables contain individual optical fibers which are tiny tubes made of glass about the width of a human hair. Unlike copper, which uses electrical voltages, fiber cables use pulses of light to represent the ones and zeros of the underlying data
File-based encryption:
File-based encryption: Guarantees confidentiality and integrity of files protected by encryption
File compression:
File compression: The files and folder structures are copied and put into an archive
File extension:
File extension: The appended part of a filename that tells us what type of file it is in certain operating systems
File handling:
File handling: A process of storing data using a program
File permissions:
File permissions: A process for setting permissions for who has access to certain files
File record number:
File record number: The index of the files entry in the MFT
File storage service:
File storage service: Allows to centrally store files and manage access between files and groups
File system:
File system: A system used to manage files
FIN_WAIT:
FIN_WAIT: A TCP socket state indicating that a FIN has been sent, but the corresponding ACK from the other end hasn’t been received yet
FIN:
FIN: One of the TCP control flags. FIN is short for finish. When this flag is set to one, it means the transmitting computer doesn’t have any more data to send and the connection can be closed
Finder:
Finder: The file manager for all Macs
FIPS (Federal Information Processing Standard):
FIPS (Federal Information Processing Standard): The DES that was adopted as a federal standard for encrypting and securing government data
Firewall:
Firewall: It is a device that blocks or allows traffic based on established rules
Firmware:
Firmware: Software that’s permanently stored on a computer component
Five layer model
Five layer model: A model used to explain how network devices communicate. This model has five layers that stack on top of each other: Physical, Data Link, Network, Transport, and Application
Fixed allocation:
Fixed allocation: Requires a manually specified list of MAC address and the corresponding IPs
Flag field:
Flag field: It is used to indicate if a datagram is allowed to be fragmented, or to indicate that the datagram has already been fragmented
Flat file:
Flat file: A collection of records/information that follow a consistent format with rules around stored values. On a host computer, one use is to have a list of network address and host name pairs (a hosts file)
Flexible single-master operations (FSMO):
Flexible single-master operations (FSMO): The single domain controller that has been tasked with making changes to the AD database that can only be made by one DC at a time
Flood guards:
Flood guards: Provide protection against DoS or Denial of Service Attacks
Flow label field:
Flow label field: 20-bit field that’s used in conjunction with the traffic class field for routers to make decisions about the quality of service level for a specific datagram
Folders/Directories:
Folders/Directories: Used to organize files
Forest:
Forest: The hierarchy above a domain that contains multiple domains, allowing accounts to share resources between domains that are in the same forest
Form factor:
Form factor: A mathematical way to compensate for irregularities in the shape of an object by using a ratio between its volume and height
Forward secrecy:
Forward secrecy: This is a property of a cryptographic system so that even in the event that the private key is compromised, the session keys are still safe
Four-Way Handshake:
Four-Way Handshake: It is designed to allow an AP to confirm that the client has the correct pairwise master key in a WPA-PSK setup without disclosing the PMK
Fragmentation:
Fragmentation: The process of taking a single IP datagram and splitting it up into several smaller datagrams
Fragmentation offset field:
Fragmentation offset field: It contains values used by the receiving end to take all the parts of a fragmented packet and put them back together in the correct order
Frame check sequence:
Frame check sequence: It is a 4-byte or 32-bit number that represents a checksum value for the entire frame
Frame control field:
Frame control field: 16 bits long, it contains a number of sub-fields that are used to describe how the frame itself should be processed
Frequency analysis:
Frequency analysis: The practice of studying the frequency with which letters appear in ciphertext
Frequency band:
Frequency band: A certain section of the radio spectrum that’s been agreed upon to be used for certain communications
FTP:
FTP: An older method used for transferring files from one computer to another, but you still see it in use today
FTTB:
FTTB: Fiber to the building, fiber to the business or even fiber to the basement, since this is generally where cables to buildings physically enter. FTTB is a setup where fiber technologies are used for data delivery to an individual building
FTTH:
FTTH: Fiber to the home. This is used in instances where fiber is actually run to each individual residents in a neighborhood or apartment building
FTTN:
FTTN: Fiber to the neighborhood. This means that fiber technologies are used to deliver data to a single physical cabinet that serves a certain amount of the population
FTTP:
FTTP: Fiber to the premises. FTTH and FTTB may both also be referred to as FTTP
FTTX:
FTTX: Stands for fiber to the X, where the X can be one of many things
Full backup:
Full backup: The full unmodified contents of all files to be backed up is are included in this backup mechanism whether the data was modified or not
Full control:
Full control: A user or group with full control that can do anything they want to files
Full disk encryption (FDE):
Full disk encryption (FDE): It is the practice of encrypting the entire drive in the system
Full duplex:
Full duplex: The capacity of devices on either side of a networking link to communicate with each other at the exact same time
Fully qualified domain name:
Fully qualified domain name: When you combine all the parts of a domain together
Functional levels:
Functional levels: The different versions of Active Directory, a functional level that describes the features that it supports
GIT:
GIT: A version control system that helps keep track of changes made to files and directories
Global:
Global: The tool that is used to group accounts into a role
Globalization:
Globalization: The movement that lets governments, businesses, and organizations communicate and integrate together on an international scale
Group policy management console (GPMC):
Group policy management console (GPMC): The tools used for creating and viewing a group policy object
Group policy objects (GPO):
Group policy objects (GPO): The ways to manage the configuration of Windows machines, referring to the objects that represent things in your network that you want to be able to reference or manage
Group policy settings reference:
Group policy settings reference: A spreadsheet that details the GPO policies and preferences that are available and where to find them
Groups:
Groups: A collection of users
Group scope:
Group scope: The way that group definitions are replicated across domains
GTK (Groupwise Transient Key):
GTK (Groupwise Transient Key): A temporal key, which is actually used to encrypt data
GUI:
GUI: A graphical user interface
GUID partition table:
GUID partition table: Only used if you are using UEFI booting
Hacker:
Hacker: Someone who attempts to break into or exploit a system
Half-duplex:
Half-duplex: It means that, while communication is possible in each direction, only one device can be communicating at a time
Half-open attacks:
Half-open attacks: A way to refer to SYN floods
Handshake:
Handshake: A way for two devices to ensure that they’re speaking the same protocol and will be able to understand each other
Hard drive:
Hard drive: It is a long term memory component that holds all of our data, which can include music, pictures, applications
Hard link:
Hard link: When created in NTFS, an entry is added to the MFT that points to the linked file record number, not the name of the file. This means the file name of the target can change and the hard link will still point to it
Hardware:
Hardware: External or internal devices and equipment that help you perform major functions
Hardware ID:
Hardware ID: A special string of characters assigned to hardware
Hardware resource deficiency:
Hardware resource deficiency: It refers to the lack of system resources like memory, hard drive space, et cetera
Hash collisions:
Hash collisions: Two different inputs mapping to the same output
Hashing (Hash function):
Hashing (Hash function): A type of function or operation that takes in an arbitrary data input and maps it to an output of a fixed size, called a hash or a digest
Having dependencies:
Having dependencies: A process of counting on other pieces of software to make an application work since one bit of code depends on another in order to work
HDD (Hard disk drive):
HDD (Hard disk drive): Hard disk drives, or HDDs, use a spinning platter and a mechanical arm to read and write information
HDMI:
HDMI: A type of cable that outputs both video and audio
HDSL:
HDSL: High Bit-rate Digital Subscriber Lines. These are DSL technologies that provision speeds above 1.544 megabits per second
Header checksum field:
Header checksum field: A checksum of the contents of the entire IP datagram header
Header length field:
Header length field: A four bit field that declares how long the entire header is. It is almost always 20 bytes in length when dealing with IPv4
Heatsink:
Heatsink: It is used to dissipate heat from our CPU
Hexadecimal:
Hexadecimal: A way to represent numbers using a numerical base of 16
HFS+/APFS:
HFS+/APFS: HFS+ is a journaling system developed by Apple Inc. and APFS is another but more encrypted Apple journaling system
Hidden files:
Hidden files: A set of files that are not visible either to avoid alteration or simply because you don?t want someone to see them
High value data:
High value data: usually includes account information, like usernames and passwords. Typically, any kind of user data is considered high value, especially if payment processing is involved
HMAC (Keyed-Hash Message Authentication Codes):
HMAC (Keyed-Hash Message Authentication Codes): It uses a cryptographic hash function along with a secret key to generate a MAC
Hop limit field:
Hop limit field: An 8-bit field that’s identical in purpose to the TTL field in an IPv4 header
Host-based firewalls:
Host-based firewalls: Protects individual hosts from being compromised when they’re used in untrusted and potentially malicious environments
Host file:
Host file: It is a flat file that contains, on each line, a network address followed by the host name it can be referred to as
Hostname:
Hostname: Used to identify the computer when it needs to talk to other computers
Hot key:
Hot key: A keyboard shortcut that does a particular task
HTTPS:
HTTPS: Hypertext Transfer Protocol Secure is a secure version of HTTP that ensures the communication your web browser has with the website is secured through encryption.
HTTP status code:
HTTP status code: The codes or numbers that indicate some sort of error or info messages that occurred when trying to access a web resource
Hub:
Hub: It is a physical layer device that broadcasts data to everything computer connected to it
Hubs:
Hubs: Devices that serve as a central location through which data travels through; a quick and dirty way of getting packets mirrored to your capture interface
Hybrid cloud
Hybrid cloud: Used to describe situations where companies might run things like their most sensitive proprietary technologies on a private cloud or on premise while entrusting their less sensitive servers to a public cloud
Hypervisor
Hypervisor: A piece of software that runs and manages virtual machines while also offering guests a virtual operating platform that’s indistinguishable from actual hardware
I/O management:
I/O management: Anything that can give us input or that we can use for output of data
I/O Streams:
I/O Streams: An input stream handles data flowing into and out of a program
IANA:
IANA: The Internet Assigned Numbers Authority, is a non-profit organization that helps manage things like IP address allocation
ICMP:
ICMP: Internet control message protocol is used by router or remote hosts to communicate error messages when network problems prevent delivery of IP packets
ICMP payload:
ICMP payload: Piece of the packet which lets the recipient of the message knows which of their transmissions caused the error being reported
Identification:
Identification: The idea of describing an entity uniquely
Identification field:
Identification field: It is a 16-bit number that’s used to group messages together
Impact:
Impact: The impact of an incident is also an important issue to consider
Implicit deny:
Implicit deny: A network security concept where anything not explicitly permitted or allowed should be denied
Import:
Import: Moving a backup of the test example policy to the production example policy
Information technology
Information technology: The use of digital technology, like computers and the internet, to store and process data into useful information
Infrastructure as a Service (IaaS):
Infrastructure as a Service (IaaS): A subset of cloud computing where a network and servers are provided for customers to run their services
Inherit only:
Inherit only: A permission group that means that a DACL will be inherited, but not applied to a container
Injection attacks:
Injection attacks: A common security exploit that can occur in software development and runs rampant on the web, where an attacker injects malicious code
Inode:
Inode: A file structure for metadata and files
Input/Output device:
Input/Output device: A device that performs input and output, including monitors, keyboards, mice, hard disk drives, speakers, bluetooth headsets, webcams, and network adapters
Install image:
Install image: A downloadable operating system image used to install an operating system on a device
Installing from source:
Installing from source: A process of installing from a source
Instantiation:
Instantiation: The actual implementation of something defined elsewhere
Instruction set:
Instruction set: A list of instructions that our CPU is able to run
Integrity:
Integrity: Means keeping our data accurate and untampered with
Interactive mode:
Interactive mode: When the parted tool launches you into a separate program
Interface:
Interface: For a router, the port where a router connects to a network. A router gives and receives data through its interfaces. These are also used as part of the routing table
Interior gateway:
Interior gateway: Interior gateway protocols are used by routers to share information within a single autonomous system
Intermediary (subordinate) CA:
Intermediary (subordinate) CA: It means that the entity that this certificate was issued to can now sign other certificates
Internet:
Internet: A worldwide system of interconnected networks
Internet Corporation for Assigned Names and Numbers (ICANN):
Internet Corporation for Assigned Names and Numbers (ICANN): Where website names are registered
Internet of Things (IoT):
Internet of Things (IoT): The concept that more and more devices are connected to the internet in a smarter fashion such as smart thermostats that turn off the air conditioner when you leave and turn it on when you come back
Internet Protocol (IP):
Internet Protocol (IP): The most common protocol used in the network layer
Internet Protocol version 4 (IPv4):
Internet Protocol version 4 (IPv4): An address that consists of 32 bits separated into four groups
Internet Protocol version 6 (IPv6):
Internet Protocol version 6 (IPv6): An address that consist of a 128 bits, four times the amount that IPv4 uses
Internet service provider (ISP)
Internet service provider (ISP): A company that provides a consumer an internet connection
Internet Service Provider (ISP):
Internet Service Provider (ISP): A company that provides a consumer an internet connection
Internetwork:
Internetwork: A collection of networks connected together through routers - the most famous of these being the Internet
Interpreted programming language:
Interpreted programming language: A language that isn’t compiled ahead of time
Intranet:
Intranet: An internal network inside a company, accessible if you are on a company?s network
Intrusion detection and intrusion protection systems (IDS/IPS):
Intrusion detection and intrusion protection systems (IDS/IPS): Operates by monitoring network traffic and analyzing it
iOS:
iOS: A mobile operating system developed by Apple Inc.
IP address:
IP address: The most common protocol used in the network layer, used to helps us route information
IP datagram:
IP datagram: A highly structured series of fields that are strictly defined
IP masquerading:
IP masquerading: The NAT obscures the sender’s IP address from the receiver
IP options field:
IP options field: An optional field and is used to set special characteristics for datagrams primarily used for testing purposes
IPsec (Internet Protocol security):
IPsec (Internet Protocol security): A VPN protocol that was designed in conjunction with IPv6
IP source guard (IPSG):
IP source guard (IPSG): It can be enabled on enterprise switches along with DHCP snooping
IPv6 tunnel:
IPv6 tunnel: IPv6 tunnel servers on either end of a connection take incoming IPv6 traffic and encapsulate it within traditional IPv4 datagrams
IPv6 tunnel brokers:
IPv6 tunnel brokers: Companies that provide IPv6 tunneling endpoints for you, so you don’t have to introduce additional equipment to your network
Issuer Name:
Issuer Name: This field contains information about the authority that signed the certificate
IT Infrastructure:
IT Infrastructure: The software, the hardware, network, and services required for an organization to operate in an enterprise IT environment
ITX (Information Technology eXtended):
ITX (Information Technology eXtended): A form factor for motherboards that is much smaller than ATX boards
Kerberos:
Kerberos: A network authentication protocol that uses tickets to allow entities to prove their identity over potentially insecure channels to provide mutual authentication
Kerckhoff’s principle:
Kerckhoff’s principle: A principle that states that a cryptosystem, or a collection of algorithms for key generation and encryption and decryption operations that comprise a cryptographic service should remain secure, even if everything about the system is known except for the key
Kernel:
Kernel: The main core of an operating system that creates processes, efficiently schedules them, and manages how processes are terminated
Kernel module:
Kernel module: It extends the kernel’s functionality so developers don’t have to actually touch the Linux kernel
Key:
Key: A crucial component of a cipher, which introduces something unique into your cipher
Key escrow:
Key escrow: Allows encryption key to be securely stored for later retrieval by an authorized party
Key length:
Key length: It defines the maximum potential strength of the system
Keylogger:
Keylogger: A common type of spyware that’s used to record every keystroke you make
Key signing parties:
Key signing parties: Organized by people who are interested in establishing a web of trust, and participants perform the same verification and signing
Key size:
Key size: It is the total number of bits or data that comprises the encryption key
KVM Switch:
KVM Switch: Keyboard, video, & mouse switch that looks like a hub that you can connect multiple computers to and control using one keyboard, mouse, and monitor
L2TP (Layer 2 Tunneling Protocol):
L2TP (Layer 2 Tunneling Protocol): It is typically used to support VPNs
Land Grid Array (LGA):
Land Grid Array (LGA): It is a type of CPU socket that stick out of the motherboard
LDAP data interchange format:
LDAP data interchange format: The tool that allows you to authenticate, add, remove users, groups, computers and so on in a directory service
LDAP Entry:
LDAP Entry: A collection of information that’s used to describe something
LDIF files:
LDIF files: A text file that lists attributes and values that describe something
Library:
Library: A way to package a bunch of useful code that someone else wrote
Lightning adaptor:
Lightning adaptor: One of the standard power, data and display connector types used in mobile devices
Lightweight Directory Access Protocol (LDAP):
Lightweight Directory Access Protocol (LDAP): An open industry-standard protocol for accessing and maintaining directory services; the most popular open-source alternative to the DAP
Line coding:
Line coding: Modulation used for computer networks
Linked:
Linked: A GPO that all of the computers or users under a domain, site, or OU will have a policy applied
Link-local unicast address:
Link-local unicast address: Allow for local network segment communications and are configured based upon a host’s MAC address
Linux OS:
Linux OS: Linux is one of the largest an open source operating system used heavily in business infrastructure and in the consumer space
Listen:
Listen: It means that a TCP socket is ready and listening for incoming connections
List folder contents:
List folder contents: A command that will execute and list folder contents and is an alias for Read and Execute
Load balancer:
Load balancer: Ensures that each VM receives a balanced number of queries
Local Area Network (LAN):
Local Area Network (LAN): A single network in which multiple devices are connected
Logging:
Logging: The act of creating log events
Logic bomb:
Logic bomb: A type of Malware that’s intentionally installed
Logic gates:
Logic gates: Allow transistors to do more complex tasks, like decide where to send electrical signals depending on logical conditions
Log rotation:
Log rotation: A way for the OS to clean out log files to make room for new ones
Logs:
Logs: Files that record system events on our computer
Logs analysis systems:
Logs analysis systems: They are configured using user-defined rules to match interesting or atypical log entries
Loopback address:
Loopback address: An IP address that always points to itself. This type of address is used to test internal pathing through the TCP/IP protocols
