CompTIA A+ domain 2 networking

HTTP (Hypertext Transfer Protocol)

Port 80. Transmits unencrypted web pages and communication across the internet.

HTTPS (Hypertext Transfer Protocol Secure)

Port 443. Delivers encrypted web communications and page transfers using SSL/TLS.

DNS (Domain Name System)

Port 53. Resolves human-readable host names into machine-readable numerical IP addresses.

DHCP (Dynamic Host Configuration Protocol)

Ports 67 (server) and 68 (client). Automatically assigns IP addresses and configuration parameters to client devices on a local subnet.

SSH (Secure Shell)

Port 22. Delivers secure, encrypted terminal access and remote command-line administration.

Telnet

Port 23. Provides unencrypted, plaintext remote command-line login across a network.

RDP (Remote Desktop Protocol)

Port 3389. Proprietary protocol providing graphical interface remote access to desktop and server environments.

SMB (Server Message Block)

Port 445. Enables shared access to files, printers, and communications between network nodes.

FTP (File Transfer Protocol)

Ports 20 (data) and 21 (control). Transfers files between computers across a network without built-in encryption.

SFTP (SSH File Transfer Protocol)

Port 22. Securely transfers and manages files over an encrypted remote shell connection.

SMTP (Simple Mail Transfer Protocol)

Port 25. Sends outgoing email between mail servers or uploads messages from a local client to an outbound server.

POP3 (Post Office Protocol version 3)

Port 110. Downloads email from a mail server to a local client, typically removing the original messages from the server.

POP3S (Post Office Protocol version 3 Secure)

Port 995. Downloads email securely from a mail server to a client using SSL/TLS encryption.

IMAP (Internet Message Access Protocol)

Port 143. Accesses and manages email directly on the server, synchronizing state across multiple client devices.

IMAPS (Internet Message Access Protocol Secure)

Port 993. Accesses and manages email directly on the server using SSL/TLS encryption for multi-device synchronization.

LDAP (Lightweight Directory Access Protocol)

Port 389. Queries, searches, and maintains centralized directory service information across a network in plaintext.

LDAPS (Lightweight Directory Access Protocol Secure)

Port 636. Queries, searches, and maintains centralized directory service information securely using SSL/TLS encryption.

NTP (Network Time Protocol)

Port 123. Synchronizes system clock time across networked devices to a common, coordinated reference clock.

SNMP (Simple Network Management Protocol)

Ports 161 (manager queries) and 162 (agent traps). Collects diagnostic metrics, monitors operational health, and manages network devices.

SIP (Session Initiation Protocol)

Ports 5060 (plaintext) and 5061 (TLS). Initiates, maintains, and terminates real-time voice, video, and multimedia sessions.

Wi-Fi 4 (802.11n)

Wireless standard operating on both 2.4 GHz and 5 GHz frequency bands, introducing MIMO technology to increase throughput.

Wi-Fi 5 (802.11ac)

Wireless standard operating exclusively on the 5 GHz band, delivering higher speeds through wider channel bandwidths and MU-MIMO.

Wi-Fi 6 / 6E (802.11ax)

High-efficiency wireless standard operating across 2.4 GHz and 5 GHz (Wi-Fi 6), expanding into the 6 GHz spectrum (Wi-Fi 6E) using OFDMA.

Wi-Fi 7 (802.11be)

Extremely High Throughput (EHT) standard supporting 2.4 GHz, 5 GHz, and 6 GHz bands with 320 MHz wide channels and Multi-Link Operation (MLO).

2.4 GHz Frequency Band

Wireless spectrum providing greater coverage distance and better solid-object penetration, but lower data rates and higher interference across fewer channels.

5 GHz Frequency Band

Wireless spectrum delivering higher data rates and reduced interference with more available channels, but offering shorter range and reduced obstacle penetration.

6 GHz Frequency Band

Ultra-fast, wide spectrum utilized by Wi-Fi 6E and Wi-Fi 7 that offers massive bandwidth and very low congestion due to zero legacy device interference.

2.4 GHz Non-Overlapping Channels

Channels 1, 6, and 11; the standard configuration used to prevent adjacent channel cross-talk and RF interference in 2.4 GHz deployments.

WPA2 (Wi-Fi Protected Access 2)

Security protocol that provides robust wireless authentication and data encryption utilizing AES (Advanced Encryption Standard) with CCMP.

WPA3 (Wi-Fi Protected Access 3)

Modern wireless security standard supporting Personal and Enterprise modes, featuring improved cryptographic strength and resistance to offline dictionary attacks.

SAE (Simultaneous Authentication of Equals)

Authentication handshake used in WPA3-Personal that replaces the standard pre-shared key exchange to mitigate passive and offline brute-force attacks.

Router

Layer 3 networking device that routes data packets between different networks, such as connecting a local area network (LAN) to a wide area network (WAN) or the internet.

Switch

Layer 2 networking device that connects multiple endpoints within the same local area network (LAN), using MAC addresses to forward frames specifically to destination ports.

Managed Switch

Network switch offering advanced administrative configuration, including VLAN creation, QoS traffic prioritization, port mirroring, and remote management.

Unmanaged Switch

Plug-and-play network switch that delivers basic Layer 2 device connectivity with fixed default settings and zero management or monitoring capabilities.

Access Point (AP)

Hardware device that connects Wi-Fi-enabled client devices to an existing wired Ethernet network infrastructure.

Firewall

Security device or program that inspects, monitors, and filters incoming and outgoing network traffic according to established security policies.

UTM (Unified Threat Management)

Comprehensive security appliance combining multiple security functions, including firewall filtering, intrusion detection and prevention (IDS/IPS), antimalware, and content inspection, into a single device.

Patch Panel

Mounted hardware assembly of network ports that terminates structured horizontal cable runs and facilitates flexible patch cord connections to switches.

Hub

Legacy Layer 1 multiport repeater that blindly broadcasts incoming electrical signals out to all connected ports, causing frequent packet collisions.

IPv4 (Internet Protocol version 4)

A 32-bit numerical addressing system expressed in dotted-decimal notation, dividing the address into four 8-bit octets.

IPv6 (Internet Protocol version 6)

A 128-bit addressing system expressed in hexadecimal notation, divided into eight 16-bit blocks separated by colons.

Subnet Mask

A 32-bit value in IPv4 networking used to differentiate the network portion of an IP address from the host portion.

Default Gateway

The IP address of the local router interface that host devices send traffic to when communicating outside their local subnet.

Dynamic IP Lease

A temporary IP address allocation provided to a client device by a DHCP server for a specified duration.

DHCP Reservation

A configuration mapping a device's physical MAC address to a specific IP address so the client consistently receives the same IP assignment.

DHCP Exclusion

A specified range of IP addresses within a DHCP scope withheld from automatic assignment to prevent conflicts with statically configured hosts.

VLAN (Virtual Local Area Network)

A logical segmentation of a physical network at Layer 2 that divides a switch infrastructure into multiple distinct broadcast domains.

VPN (Virtual Private Network)

A security technology that encapsulates and encrypts network traffic across an untrusted or public network, establishing a secure communications tunnel.

LAN (Local Area Network)

A network that interconnects computers and devices within a limited geographical area, such as a home, school, or single office building.

WAN (Wide Area Network)

A telecommunications network extending across large geographic distances, interconnecting multiple smaller networks across cities, countries, or continents.

MAN (Metropolitan Area Network)

A high-speed network spanning a geographic area larger than a local facility but smaller than a wide area network, typically covering an entire city or campus.

PAN (Personal Area Network)

A very short-range network centered around an individual's workspace, typically connecting peripherals and mobile devices via Bluetooth or USB.

WLAN (Wireless Local Area Network)

A local area network that links two or more devices using wireless communication methods, most commonly based on IEEE 802.11 standards.

Cable Broadband (DOCSIS)

High-speed internet delivered over coaxial or hybrid fiber-coaxial (HFC) TV lines utilizing Data Over Cable Service Interface Specification standards.

DSL (Digital Subscriber Line)

A broadband technology transmitting digital data over traditional copper telephone lines across high-frequency bands that do not disrupt voice phone service.

Fiber (FTTH / Fiber to the Home)

A broadband connection delivering data as pulses of light over optical glass cables directly to residences, offering high bandwidth and symmetrical upload/download speeds.

Satellite Internet (Geostationary)

A wireless internet connection communicating with satellites positioned in high geostationary orbit, providing broad remote coverage but characterized by higher latency.

Cellular Broadband (LTE / 5G)

Wireless wide area network connectivity provided through cellular base stations and antennas to deliver mobile data and voice access across licensed radio bands.

Starlink (LEO Satellite)

A satellite internet constellation operating in Low Earth Orbit (LEO) designed to deliver high-speed broadband with substantially lower latency than traditional geostationary systems.

Cable Tester

• Function: Verifies the physical integrity and continuity of a network cable (RJ-45, coaxial, etc.).

• Key Details: Checks for wiring faults such as breaks, shorts, crossed wires, and miswirings (split pairs). Consists of a main unit and a remote terminator.

Crimper (Crimping Tool)

• Function: Attaches modular connectors (such as RJ-45 or RJ-11 ends) onto the bare stripped ends of unshielded twisted-pair (UTP) copper cable.

• Key Details: Deforms the metal pins inside the connector to pierce the wire insulation and firmly grip the cable jacket.

Punch-Down Tool

• Function: Terminates individual solid-core wires of a network cable into IDC (Insulation Displacement Connector) blocks, such as 110-blocks, patch panels, or keystone jacks.

• Key Details: Simultaneously pushes the wire into the metal terminal slot and automatically trims the excess wire end.

Tone Generator and Probe ("Fox and Hound")

• Function: Used to trace the exact physical path of a cable through walls, ceilings, or dense wiring bundles.

• Key Details:

  • Generator ("Fox"): Connects to one end of the cable and injects an audible tone signal.

  • Probe ("Hound"): Wand is swept near cable bundles to audibly detect the tone without needing to touch bare copper.

Loopback Plug

• Function: Tests physical network ports (Ethernet, serial, USB) to verify if the port can successfully send and receive data.

• Key Details: Physically reroutes transmitting pins directly back into receiving pins so a diagnostic utility can test interface communication and transceiver functionality.

Multimeter

• Function: Measures electrical properties across hardware components and circuits.

• Key Details: Measures AC/DC voltage (e.g., power supply outputs), resistance/continuity (checking if a fuse or wire is intact), and current (amperage).