CompTIA A+ 220-1101 Core 1 Personal Flashcards (Simplified & Concise Definitions)

Personal set where I edited several definitions to be more correct and concise. Also added some terms. Verify accurate definitions before use because the ones I didn't edit might still be inaccurate or too long.

Local Area Network (LAN)

A small network such as one building or floor
(1.1 & 2.7)

OS not found

• Usually indicates corrupted/fault MBR (Master Boot Record) or GPT (Globally Unique ID Partition Table)

• To fix, reboot into the Windows recovery mode and use the 'bootrec /fixboot' command to fix the GPT

Port 427

• Protocol for organizing and locating resources (e.g. printers, disk drives, databases, e-mail directories, and schedulers) in a network

• Alternative to LDAP

3G

• 2 Techs used: HSPA+ and EV-DO

• HSPA+ (Evolved High-Speed Packet Access) 3G standard used in GSM cellular networks

• EV-DO (Evolution-Data Optimized) 3G standard used for CDMA cellular networks

4G

• 4G cellular technology is made up of LTE and LTA-A.

• Long Term Evolution (LTE) is a packet data communications specification providing an upgrade path for both GSM and CDMA2000 cellular networks

5G

• Made up of three different types: low-band, mid-band, and high-band mmWave technology.

Zigbee and Z-Wave

• Both wireless communication protocols used for home automation

• Zigbee is open-source; 2.4 GHz

• Z-Wave is proprietary

Virtual Machines and Cloud Security

• VM Sprawl: Uncontrolled growth of VMs due to poor management, leading to security risks & resource drain.

• Data Remanence: Residual data left on storage after deletion, posing a security risk.

SSID (Service Set Identifier)

• It’s the name of a Wi-Fi network.

• It helps devices identify and connect to the correct wireless network.

• Can be broadcasted (visible) or hidden (manual entry required).

• Changing the default SSID enhances security but does not prevent attacks.

Bandwidth Saturation

• Bandwidth is the maximum data transfer rate of a network, measured in Mbps or Gbps.

• Bandwidth Saturation occurs when the network's full capacity is used, leading to slow speeds.

• Causes: High traffic, streaming, large downloads, too many devices.

• Solutions: QoS (Quality of Service), upgrading bandwidth, reducing unnecessary traffic.

Hub

• Simple, legacy networking device

  • Replaced by switches for better efficiency and security

• Connects multiple devices on a LAN

• Broadcasts all incoming data to every connected device/port

  • No traffic filtering or directing (unlike switch)

  • Causes network congestion

• Operates at Layer 1 (Physical Layer) of the OSI model

Laser Printer Power & DC Voltages

• Laser printers use a DC power supply (DCPS) to convert AC to DC.

• Common voltages:

  • +5 VDC & -5 VDC → Power the logic board.

  • +24 VDC → Powers motors for paper movement.

• Not used: -24 VDC (Not found in standard laser printers).

Laptop Terms

1. [External] Power Adapter

2. DC Jack

• Charger

• Laptop Charging Port (converts the AC power from the wall into DC power)

IaaS vs SaaS

• IaaS → Raw infrastructure (servers, storage, networking). Full control over OS, apps, and configs. Use case: Hosting custom apps while managing everything.

• PaaS → Managed platform (OS, runtime, databases). Focus on coding, not infrastructure. Use case: Developers deploying apps without server maintenance.

Thin Clients

Thin Client Basics:

• Thin Client → Lightweight computer relying on a remote server.

• VDI → Virtual desktops run on a central server, not locally.

• Benefits → Lower cost, easy management, better security.

Setup Steps:

1. Connect to Network (Ensure internet/LAN access).

2. Install VDI Client (Configure connection to VDI).

3. Set Up User Credentials (Login for virtual desktop access).

Optical Disc Storage Sizes

• CD: 700 MB.

• DVD: 4.7 GB for single-layer disc & 8.5 GB for a dual-layer disc.

• Blu-ray: 25 GB for a single-layer disc & 50 GB for a dual-layer disc.

Hybrid vs Community Cloud

• Hybrid Cloud → Mix of on-premises and public cloud. Moves data/apps as needed. Example: Store sensitive data locally, use cloud for scalability.

• Community Cloud → Shared by organizations with similar needs (e.g., government, healthcare). Not for integrating on-prem with cloud.

Conflated Virtualization Terms

• Hypervisor → Software that runs VMs.

  • Type 1 (Bare-metal) → Runs directly on hardware. Faster.

  • Type 2 (Hosted) → Runs on a host OS. Slower.

• VT (Intel) / AMD-V → Hardware features for better virtualization.

• Not Virtualization:

  • HyperThreading (Intel) / SMT (AMD) → CPU tech for running multiple threads per core.

CDMA vs GSM

CDMA (Code Division Multiple Access):

• No SIM card (built-in carrier lock)

• Used mainly in the U.S. (Verizon, Sprint)

• Limited global compatibility

• Older technology

GSM (Global System for Mobile Communications):

• Uses SIM cards (easy device swapping)

• Global standard (AT&T, T-Mobile, most of the world)

• Better for international use

Key Difference:

• GSM = SIM flexibility

• CDMA = Carrier-locked

Note:

• Both are legacy technologies—replaced by 4G LTE and 5G, which support SIM-based, global communication.

Components of CDMA

• PRL (Preferred Roaming List) → Lists which towers to use when roaming (carrier-updated).

• PRI (Product Release Information → Stores network settings for carrier communication (carrier-updated).

• Baseband Updates → Firmware updates to Improve phone radio connectivity.

• IMSI (International Mobile Subscriber Identity) → Identifies a mobile user (common in GSM, relevant for LTE).

• ESN/MEID (Electronic Serial Number/Mobile Equipment Identifier) → Unique hardware ID for CDMA phones (no SIM card needed).

PRL (Preferred Roaming List)

Lists which towers to use when roaming for CDMA phones (carrier-updated).

PRI (Product Release Information)

Stores network settings for carrier communication for CDMA phones (carrier-updated).

Baseband Updates

Firmware updates for the phone’s radio to improve connectivity.

Subnet Mask

Divides IP address into two parts:

• Network ID (which network you're on)

• Host ID (specific devices on that network)

• Used by routers and devices to determine if a device is local or remote.

• Helps route packets within and between networks.

• Common subnet masks:

  • 255.255.255.0 → Class C (supports up to 254 hosts)

  • 255.255.0.0 → Class B

  • 255.0.0.0 → Class A

What should you do if the power supply’s fan is not working?

• If the fan in power supply is faulty, replace entire power supply

• Never attempt to repair or fix broken power supply or broken power supply cooling fan due to the power supply's high voltage electrical components.

• When a fan creates grinding sounds, this is evidence of impending failure and device needs to be replaced

127.0.0.1

• Localhost IP for testing your network interface card (NIC).

• Reserved for loopback test.

• No communication of the return packet indicates network card is faulty, the cable/loopback is loose, or bad wiring of loopback plug.

• Using ping with public IP addresses or the gateway address, such as 1.1.1.1, 8.8.8.8, and 192.168.1.1, would instead verify the entire path and not just NIC's driver.

CompTIA Troubeshooting Methodology

1. Identify the problem

2. Establish a theory of probable cause

3. Test the theory to determine the cause

4. Establish a plan of action & Implement the solution

5. Verify full system functionality & Implement Preventative Measures

6. Document findings, actions, outcomes

Hotspot

Phone acts as router to provide wireless connection to internet for other devices

• Creates wireless network multiple devices can connect to

• Allows multiple devices to access internet through phone

Tethering

Phone acts as modem to provide (often wired) connection to internet for other devices

• Can also use Bluetooth or WiFi for this, but WiFi is called hotspot

• Direct connection

• One device uses phone’s connection to access internet

• More secure than hotspot

Printer control language

• Page description language

• Used to tell printers how to properly layout and print the contents of a document on a page.

• Common and supported by many different printer manufacturers. HTML is used for websites and online, not printing pages.

Line Printer Daemon & Internet Printing Protocl

• The Internet Printing Protocol (IPP) is a specialized Internet protocol for communication between client devices and printers (or print servers) using the HTTP protocol for data transport.

• The Line Printer Daemon (LPD) protocol is a network printing protocol for submitting print jobs to a remote printer. LPD is an older protocol than IPP.

VM Network Connection Types

• Localhost: The VM can only communicate with itself

• Private: VMs can only communicate with other VMs on same virtual network but not with the host or the internet

• Internal: The VM can communicate with the host and other VMs on the same network

• External: The VM can connect to the internet, the host, and other machines on the same network

Page Description Languages

• Both are page description languages used to tell printers how to properly layout and print the contents of a document on a page.

• Printer Control Language (PCL) produces faster outputs that are of lower quality.

• PostScript (PS) is slower but produces higher quality outputs.

• The Internet Printing Protocol (IPP) is a specialized Internet protocol for communication between client devices and printers (or print servers) using the HTTP protocol for data transport.

• The Line Printer Daemon (LPD) protocol is a network printing protocol for submitting print jobs to a remote printer. LPD is an older protocol than IPP.

2.4 GHz vs 5.0 GHz

• 5.0 GHz has more channels than 2.4 GHz, so less congestion and interference, allowing higher data rates

• 2.4 GHz has a longer wavelength making it better at propagating through solid surfaces while also giving it a longer range at the same power output levels

NS (Nameserver)

Indicates which DNS server is authoritative for that domain

A (Address)

Indicates the IPv4 address of a given domain

AAAA (Quad A)

Used to map the IPV6 to its respective domain name

CNAME (Canonical Name)

Maps an alias name to a true domain name.

• These records are typically used to map a subdomain such as www or mail to the domain hosting that subdomain's content

TXT (Text Records)

Allows owner to insert text into DNS records, often for verification, policy info, or email security
(2.6)

Campus Area Network (CAN)

A computer network that connects two or more LANs that are located on a campus.

Personal Area Network (PAN)

- Provides communication for devices owned by a single user that work over a very short distance
- Bluetooth, IR, NFC, etc.
(1.1 & 2.7)

MAN (Metropolitan Area Network)

- A network covering a city
- Bigger than LAN, usually smaller than WAN
- Common to see government ownership
(2.7)

SAN (Storage Area Network)

Specialized, high-speed network that provides block-level network access to storage.
(2.7)

WLAN (Wireless Local Area Network)

A wireless local area network
(2.7)

USB 1.1

• 12 Mbps

• 2.5W

USB 2.0

• 480 Mbps

• 2.5W

USB 3.0

• 5 Gbps

• 4.5W

Port 69

• Used for Trivial File Transfer Protocol (TFTP)

• Lightweight Version of FTP

Port 137, 138, 139

• Used for NetBIOS services, including name resolution and file sharing.

• Allows computers to communicate with each other over a network

• Uses TCP protocol

• Facilitating communication and file sharing in Windows networks.

• Used before SMB

LCD (Liquid Crystal Display)

Lightweight & Inexpensive - Poor black levels due to separate Backlight - Traditionally used fluorescent backlights, now uses LED backlight
(1.2)

LED

An LCD display that uses an LED backlight instead of a fluorescent one

TN (twisted nematic)

Fast response Times - Low cost - Low Power Use - Limited Viewing Angles - Used in LCD displays
(1.2)

IPS (In Plane Switching)

Best Colors - Better Viewing Angles - More Expensive - Used in LCD displays
(1.2)

VA (Vertical Alignment)

Best Contrast - Slower response times than TN - Used in LCD displays

OLED (organic light-emitting diode)

Doesn't have backlight - Better Contrast than LCD - Does not use TN, IPS, or VA
(1.2)

Plasma

Display type uses tiny cells filled with noble gas and mercury that creates plasma when voltage is applied; plasma hits phosphor to produce light

QLED

Quantum Light Emitting Diode - Type of LCD - Thousands of tiny LED backlights enhance color accuracy & brightness

MDM

Mobile device management: Allows company to manage employee devices
- Centralized management system
- Ensures device security
(1.4)

MAM

Mobile Application management:
- Set policies & restrictions on apps
- Control Company software (Update, Remove, Etc.)
(1.4)

UDP

User Datagram Protocol. A protocol used on the internet for fast transmission of information but with minimal error checking

• Connectionless protocol that allows data to be sent without establishing a connection, prioritizing speed over reliability.

TCP/IP

The very popular suite of network protocols that includes TCP, IP, UDP & dozens of other protocols
- These communication protocols allow devices to transfer data and communicate over the internet

TCP

Transmission Control Protocol

• Provides reliable, ordered, and error-checked delivery of a stream of packets on the internet.

• Guarantees packet delivery via use of virtual circuit and data acknowledgment

• Connection-oriented, so slower

• Verifies integrity of delivered packets

PRL (Preferred Roaming List)

- Allows phone to connect to the right tower
(1.4)

Port 20, 21

FTP (File Transfer Protocol)

• Used for transferring files from one host to another

• Uses TCP

• Insecure
  (2.1)

Port 22

SSH (Secure Shell) - TCP protocol

• Encrypted Communication

• Secure version of Telnet

• Allows remote access to computers, like telnet

• (2.1)

Secure File Transfer Protocol (SFTP) - TCP

• secure file transfer protocol. It runs over the SSH protocol. It supports the full security and authentication functionality of SSH.

Port 23

Telnet (Telecommunications Network) - TCP Protocol
- Non-encrypted remote control of computer
- Log into devices remotely
(2.1)

Port 25

SMTP (Simple Mail Transfer Protocol)
- TCP protocol
- Used to send email (outbound mail)
(2.1)

Port 53

DNS (Domain Name System)
- Uses both UDP and TCP Protocol, but moreso UDP
- Converts hostnames (URL addresses) to IP addresses
- CRITICAL Resource
(2.1)

Port 67, 68

DHCP (Dynamic Host Configuration Protocol)
- UDP Protocol
- Automated assignment & and configuration of IP addresses to devices
- IPs can be reserved for certain devices
- IP Range: 10.1.10.10 through 10.1.10.199
(2.1)

Port 80

HTTP (Hypertext Transfer Protocol)

• Uses TCP protocl

• Manages non-encrypted communication between web server and client in the browser
  (2.1)

Port 110

POP3 (Post Office Protocol 3)

• Uses TCP Protocol
  - Receive emails from an email server
  - Has been mostly replaced by IMAP
  (2.1)

Port 143

IMAP (Internet Mail Access Protocol)

• Uses TCP protocl

• Allow management of email inboxes across multiple clients. (Sync email across multiple devices)
  (2.1)

• Secure protocol designed to receive and download email

Port 161, 162

SNMP (Simple Network Management Protocol)

• Uses UDP protocol

• Used to ensure proper operation of network by gathering and managing network performance info
  (2.1)

Port 389

LDAP (Lightweight Directory Access Protocol)

• Uses TCP protocol

• Store & retrieve info in a network directory.

• Provides access to info across clients on network (2.1)

Port 443

HTTPS (Hyper Text Transfer Protocol Secure)

• Uses TCP protocol

• Encrypts the communication between web server and client (2.1)

• Small padlock indicates website is using HTTPS

Port 445

Server Message Block (SMB) & Common Internet File System (CIFS)

• Uses TCP protocol

SMB:

• Provides shared access and easy visibility to network resources like files and printers

• Has more options and commands than FTP (like connecting to printers)

• CIFS is an enhanced version of SMB that works across operating systems

• Superseded NetBIOS

Port 3389

RDP (Remote Desktop Protocol)

• Uses TCP protocol

• Allows remote access to desktop

• Whatever you can do at the remote computer, you can do on the RDP client
  (2.1)

(Wireless) Access Point (WAP)

Extends wired network & converts it into a wireless network.
(2.2)

Router

Routes traffic between IP subnets
(2.2)

Patch Panel

A patch panel is a central hardware component used in networking to organize and manage cable connections. It provides a fixed interface where multiple network cables from wall outlets or devices terminate, allowing easy reconfiguration of network connections.

• Used in: Data centers, offices, and structured cabling systems.

• Purpose: Simplifies cable management, reduces wear on switches, and allows for quick troubleshooting.

• Types: Ethernet patch panels (RJ45) and fiber patch panels.
  

• (2.2)

Firewalls

• Network security device or software that monitors and controls incoming and outgoing traffic based on security rules.

• Acts as a barrier between a trusted internal network and untrusted external networks like the internet.

• Blocks unauthorized access

• Prevents malware and cyberattacks

• Controls network traffic (e.g., blocking certain websites or ports)

• Can implement VPNs, intrusion prevention, and logging
  (2.2)

PoE (Power over Ethernet)

Devices that send Ethernet data and power over twisted-pair cable to compliant devices (for example, cameras, phones, etc).
(2.2)

Modem

• Converts digital data from a computer into a signal that can be transmitted over an ISP’s network and vice versa.

• Types:

  • Cable: Uses DOCSIS over coaxial cable (broadband).

  • DSL: Uses ADSL/VDSL over phone lines.

  • Fiber (ONT): Used for fiber-optic connections.

  • Dial-Up: Legacy tech using phone lines (very slow).

• Common Issue: No internet? Check connections & restart the modem.
  (2.2)

ONT (optical network terminal)

- Fiber
- ISP fiber line stretches to demarc point at which your in-home copper wire takes over.
(2.2)

NIC (Network Interface Card)

- A device that serves as an interface between the computer and the network. Also called a network adapter or network card.
- Ethernet Connection
- May need drivers installed before hardware is installed (Check Manual)
(2.2)

What is the 802.11a standard?

5GHz & 54 Mbps (released in 1999)

What is the 802.11b standard?

2.4GHz & 11 Mbps (released in 1999)

What is the 802.11g standard?

2.4GHz & 54 Mbps (released in 2003)

What is the 802.11n standard?

2.4/5GHz & 600 Mbps (released in 2009)

What is the 802.11ac standard?

5GHz & 6.9 Gbps (released in 2014)

What is the 802.11ax standard?

2.4/5GHz & 9.6 Gbps (released 2021)

802.11s

Wireless Mesh networking (WDS-Wireless Distribution System

802.3af

Provides up to 15.4W of power up to 100 meters over Ethernet

802.3at

Provides up to 25W of power up to 100 meters over Ethernet

802.3bt (Type 3)

Provides up to 60W of power over Ethernet

802.3bt (Type 4)

Provides up to 100W of power over Ethernet

DNS Server

- Converts a website name to an IP Addresses
- Usually managed by ISP or enterprise IT Dept.
(2.4)

DHCP Server

- The server leases IP addresses to network clients
- IP Range: 10.1.10.10 through 10.1.10.199
(2.4)

File Server

- Centralized Storage of documents, files, etc.
- Standard system of file management
- SMB (Server Message Block)
- AFP (Apple Filing Protocol)
(2.4)

Print Server

- Connect a printer to the network
- Provide printing services for all network devices
- May be built-in to the printer
- Uses standard printing protocols
- SMB (Server Message Block),
- IPP (Internet Printing Protocol),
- LPD (Line Printer Daemon)
(2.4)