A+ C1

Q: What is a form factor?

A: The physical size, shape, and layout of a hardware component — determines compatibility (e.g., SO-DIMM vs DIMM, M.2 vs 2.5 inch, ATX vs Mini-ITX)

Q: What does SO-DIMM stand for?

A: Small Outline Dual In-line Memory Module — the smaller RAM form factor used in laptops

Q: What happens if laptop RAM is soldered to the motherboard?

A: It cannot be upgraded — entire motherboard must be replaced

Q: What are the two storage form factors used in laptops?

A: 2.5 inch (HDD or SSD) and M.2

Q: What is the advantage of M.2 over a 2.5 inch drive in a laptop?

A: Smaller form factor, single connection, easier installation

Q: What is imaging/cloning software used for?

A: Creates an exact duplicate of one drive onto another — used when upgrading from HDD to SSD

Q: How can you diagnose whether a laptop keyboard problem is hardware or OS-related?

A: Plug in an external USB keyboard — if it works, the issue is with the built-in keyboard hardware

Q: What wireless card types provide 802.11 in older laptops?

A: Mini PCI or Mini PCIe cards

Q: What is Bluetooth's network classification?

A: PAN — Personal Area Network

Q: What are the two Windows Hello biometric authentication methods?

A: Windows Hello Face (facial recognition) and Windows Hello Fingerprint

Q: What is NFC and what is its typical range?

A: Near Field Communication — ~4 cm or less; used for payments, access control, and authentication

1.2 Connecting Mobile Devices

Q: What is USB-C's key physical advantage over older USB connectors?

A: Reversible — plugs in either orientation; also carries video signals like DisplayPort and HDMI

Q: What is Apple's Lightning connector?

A: A proprietary 8-pin Apple connector used on older iPhones/iPads; reversible

Q: What is the difference between a hotspot and tethering?

A: Hotspot = multiple devices share your phone's internet; Tethering = only one device connects

Q: What is a TRRS connector?

A: Tip-Ring-Ring-Sleeve — a 3.5mm analog audio jack used for wired headsets

Q: What is a docking station?

A: Connects/disconnects a laptop from all peripherals at once; can support full-size adapter cards; laptop-specific

Q: What is the difference between a docking station and a port replicator?

A: Docking stations are laptop-specific and support adapter cards; port replicators connect via USB and work with almost any laptop

Q: What is Bluetooth pairing and when do you have to do it?

A: A one-time setup process using a PIN to securely connect two Bluetooth devices — after pairing, they reconnect automatically

1.3 Mobile Device Networks

Q: What does LTE stand for and what generation is it?

A: Long-Term Evolution — 4G

Q: What does GSM stand for?

A: Global System for Mobile Communications — the technology 4G is based on; uses SIM cards

Q: When was 5G introduced?

A: 2020

Q: What is a SIM card and what does it store?

A: Subscriber Identity Module — stores carrier info, phone number, subscriber ID, contacts, and messages

Q: What is an eSIM?

A: An embedded SIM built into the phone — transferred between devices via software or QR code, no physical swap

Q: How many satellites must a phone see for accurate GPS?

A: Four

Q: What are two alternatives to GPS for location when GPS is unavailable?

A: Wi-Fi triangulation and cellular tower triangulation

Q: What is airplane mode?

A: Disables all wireless communication on a device (cellular, Wi-Fi, Bluetooth) — individual radios can be re-enabled manually after

Q: What are the two main Wi-Fi frequency bands?

A: 2.4 GHz (longer range, slower, more interference) and 5 GHz (shorter range, faster, less interference)

1.4 Mobile Device Management

Q: What is MDM?

A: Mobile Device Manager — centrally manages and enforces policies on mobile devices in an organization

Q: What does BYOD stand for?

A: Bring Your Own Device — employee uses their personal phone for work

Q: What does COPE stand for?

A: Corporate Owned, Personally Enabled — company owns and controls the device but allows personal use

Q: What does CYOD stand for?

A: Choose Your Own Device — employee selects from a company-approved list of devices

Q: What can an MDM control on a device?

A: Apps, camera, GPS, screen locks, email config, sync settings, MFA requirements, and more

Q: What is the purpose of partitioning on a BYOD device via MDM?

A: Separates personal data from corporate data on the same phone

Q: What is an IMEI?

A: International Mobile Equipment Identity — unique identifier for a mobile device

2.1 - Introduction to IP

Q: What is Messer's networking analogy for IP?

A: Network = roads. IP = the truck. TCP/UDP = boxes on the truck. Data = what's inside the boxes.

Q: What is encapsulation?

A: Wrapping data in layers of headers as it travels down the network stack — e.g., HTTP inside TCP inside IP inside Ethernet

Q: What is TCP?

A: Transmission Control Protocol — connection-oriented, reliable; uses acknowledgments, error recovery, and flow control

Q: What does "connection-oriented" mean in TCP?

A: A formal session is established before data is sent and formally closed after — like saying hello and goodbye on a phone call

Q: What is UDP?

A: User Datagram Protocol — connectionless, no acknowledgments, no retransmission, best effort delivery

Q: Why use UDP over TCP?

A: When real-time delivery matters more than reliability — VoIP and video streaming use UDP because lost data can't be rewound

Q: What protocols use TCP?

A: HTTP, HTTPS, SSH, FTP, SMTP, IMAP, POP3, RDP, Telnet, LDAP

Q: What protocols use UDP?

A: DHCP, DNS, TFTP, VoIP, video streaming, SNMP

Q: What is a port number?

A: A number that identifies which application receives incoming data — like a room name written on a box

Q: What is a nonephemeral (well-known) port?

A: A fixed permanent port used by servers/services — ports 0-1,023

Q: What is an ephemeral port?

A: A temporary randomly assigned client-side port for one session — ports 1,024-65,535; discarded after the session ends

Q: What is the full port number range for TCP and UDP?

A: 0-65,535 — TCP port 80 and UDP port 80 are NOT the same

Q: Are port numbers a security mechanism?

A: No — they are reference numbers only, not a security feature

Q: What is multiplexing in networking?

A: Sending multiple types of traffic simultaneously using different port numbers — enabled by TCP/UDP

2.1 - Common Ports (must memorize cold)

Q: What port does FTP use and for what?

A: TCP 20 (active data transfer) and TCP 21 (control/administration)

Q: What port does SSH use?

A: TCP 22 — encrypted remote command line access

Q: What port does Telnet use and what's the key difference from SSH?

A: TCP 23 — same function as SSH but sends everything unencrypted (in the clear)

Q: What port does SMTP use?

A: TCP 25 — sends email between servers

Q: What port does DNS use?

A: UDP 53 (also TCP 53 for large transfers) — resolves domain names to IP addresses

Q: What ports does DHCP use?

A: UDP 67 (server) and UDP 68 (client) — automatically assigns IP addresses

Q: What port does HTTP use?

A: TCP 80 — unencrypted web traffic

Q: What port does HTTPS use?

A: TCP 443 — encrypted web traffic using TLS

Q: What port does POP3 use?

A: TCP 110 — downloads email to local device

Q: What port does IMAP use?

A: TCP 143 — syncs email across multiple devices/clients

Q: What port does SMB use and what is SMB?

A: TCP 445 — Server Message Block; used for Windows file sharing and printer queues

Q: What port does LDAP use?

A: TCP 389 — Lightweight Directory Access Protocol; used to query directory services like Active Directory

Q: What port does RDP use?

A: TCP 3389 — Remote Desktop Protocol; remotely controls Windows desktops

Q: What is NetBIOS and what ports does it use?

A: Older Windows protocol — UDP 137 (name service) and TCP 139 (session/file transfer); replaced by SMB on port 445

2.2 - Wireless Network Technologies

Q: What organization standardizes Wi-Fi and what is the standard called?

A: IEEE — 802.11 Committee; networks are called 802.11 networks

Q: What are the Wi-Fi generation names?

A: 802.11ac = Wi-Fi 5 | 802.11ax = Wi-Fi 6/6E | 802.11be = Wi-Fi 7

Q: What three frequency bands do Wi-Fi networks use?

A: 2.4 GHz, 5 GHz, and 6 GHz

Q: What is the difference between 2.4 GHz and 5 GHz Wi-Fi?

A: 2.4 GHz = longer range, slower, more interference (only 3 non-overlapping channels); 5 GHz = shorter range, faster, less interference, more channels

Q: What frequency does Bluetooth use?

A: 2.4 GHz — same ISM band as 2.4 GHz Wi-Fi

Q: What is the ISM band?

A: Industrial, Scientific, and Medical — unlicensed 2.4 GHz spectrum; shared by Bluetooth, Wi-Fi, microwaves

Q: What is RFID and how does it work?

A: Radio Frequency Identification — passive tags have no battery; power from scanner's radio frequency activates the tag which sends back an ID code

Q: What is NFC and how does it extend RFID?

A: Near Field Communication — builds on RFID by adding two-way communication; used for payments, access control, and device pairing

Q: What is the max range of consumer Bluetooth devices?

A: ~10 meters

2.3 - Network Services

Q: What is DNS and what does it do?

A: Domain Name System — translates fully qualified domain names (like professormesser.com) into IP addresses

Q: What is DHCP?

A: Dynamic Host Configuration Protocol — automatically assigns IP address, subnet mask, default gateway, and DNS server to devices on a network

Q: What is the DORA process?

A: The 4-step DHCP process: Discover → Offer → Request → Acknowledge

Q: What is SMB?

A: Server Message Block — Windows protocol for file sharing, printer queues, and device communication; also called CIFS

Q: What is a SIEM?

A: Security Information and Event Manager — central server that consolidates syslog data from all devices for correlation and analysis

Q: What is a proxy server?

A: A server that receives client requests, forwards them to the destination, evaluates the response, and returns it to the client — used for security, caching, and content filtering

Q: What is a load balancer?

A: Distributes incoming requests evenly across multiple servers — automatically removes failed servers from rotation

Q: What is SCADA/ICS?

A: Supervisory Control and Data Acquisition / Industrial Control System — manages large-scale industrial equipment (power, oil, manufacturing) over a network

Q: What is an AAA server?

A: Authentication, Authorization, and Accounting server — verifies credentials and controls access to network resources

Q: What is NTP?

A: Network Time Protocol — keeps all devices synchronized to the correct date and time; critical for logs and encryption

Q: What is a UTM?

A: Unified Threat Management — all-in-one security appliance combining firewall, IPS, content filtering, spam filter, and VPN

Q: What is an embedded system?

A: A purpose-built device where the OS is not directly accessible to the user — e.g., fire alarm systems, time clocks

2.4 - DNS Configuration

Q: What is a DNS A record?

A: Maps a hostname to an IPv4 address

Q: What is a DNS AAAA record?

A: Maps a hostname to an IPv6 address (quad-A record)

Q: What is a DNS CNAME record?

A: Canonical Name — an alias that points one hostname to another (e.g., www → mail.example.com)

Q: What is a DNS MX record?

A: Mail Exchanger — specifies which server handles email for a domain

Q: What is a DNS TXT record?

A: A human-readable text record stored in DNS — used for SPF, DKIM, and DMARC email verification

Q: What is SPF?

A: Sender Policy Framework — a TXT record listing authorized email servers for a domain; prevents spoofing

Q: What is DKIM?

A: Domain Keys Identified Mail — digitally signs outgoing email with a private key; receiving servers verify using the public key in DNS

Q: What is DMARC?

A: Domain Based Message Authentication Reporting and Conformance — tells receiving servers what to do with emails that fail SPF/DKIM checks (allow, quarantine, or reject)

Q: What command queries DNS on Linux/macOS?

A: dig — e.g., dig www.professormesser.com