networking job prep

LAN (Local Area Network)

A network that connects devices within a small area like a home, office, or school.

WAN (Wide Area Network)

A network that connects multiple LANs across large distances, such as the Internet.

MAN (Metropolitan Area Network)

A network that spans a city or large campus.

PAN (Personal Area Network)

A very small network around one person, such as Bluetooth devices connected to a phone.

NIC (Network Interface Card)

The hardware inside a computer that allows it to connect to a network.

Bandwidth

The maximum amount of data that can travel across a network connection in a given amount of time.

Throughput

The actual amount of data successfully transferred across the network.

Latency

The delay it takes for data to travel from one device to another.

Packet

A small unit of data sent across a network.

Frame

A packet wrapped with Layer 2 information, including MAC addresses.

MTU (Maximum Transmission Unit)

The largest packet size that can be sent without being broken into smaller pieces.

IP (Internet Protocol)

Gives every device an address so data knows where to go.

IPv4

The most common addressing system using 32-bit addresses (example: 192.168.1.1)

IPv6

A newer addressing system using 128-bit addresses to support far more devices.

MAC Address

A unique physical address permanently assigned to a network card.

TCP (Transmission Control Protocol)

A reliable protocol that guarantees data arrives correctly and in order.

UDP (User Datagram Protocol)

A faster protocol that sends data without checking if every packet arrives.

Port Number

A number that identifies which application or service should receive network traffic.

Socket

A combination of an IP address and port number that identifies a communication endpoint.

20/21 FTP

Used for transferring files between computers.

22 SSH

Securely connects to another computer through the command line.

23 Telnet

An older, insecure remote login protocol.

25 SMTP

Sends email between mail servers.

53 DNS

Resolves domain names into IP addresses.

67/68 DHCP

Automatically assigns IP addresses to devices.

80 HTTP

Loads standard, unencrypted web pages.

110 POP3

Downloads email to a client.

143 IMAP

Synchronizes email between devices and the mail server.

161 SNMP

Used to monitor and manage network devices.

389 LDAP

Used for directory services like Active Directory.

443 HTTPS

Loads encrypted and secure websites.

3389 RDP

Allows remote control of Windows computers.

Layer 1 – Physical

Sends raw electrical, optical, or radio signals through cables or wireless.

Layer 2 – Data Link

Uses MAC addresses to move data between devices on the same network.

Layer 3 – Network

Uses IP addresses to route data between different networks.

Layer 4 – Transport

Uses TCP or UDP to control how data is delivered.

Layer 5 – Session

Starts, manages, and ends communication sessions.

Layer 6 – Presentation

Formats, compresses, and encrypts data.

Layer 7 – Application

Provides network services directly to applications like web browsers.

Router

Connects different networks and directs traffic between them.

Switch

Connects devices within the same LAN using MAC addresses.

Hub

Sends incoming data to every connected device; largely obsolete.

Modem

Connects your local network to your Internet Service Provider.

Firewall

Filters network traffic to block unauthorized access.

Access Point (AP)

Provides wireless Wi-Fi access to a network.

Patch Panel

Organizes Ethernet cables in server rooms.

Rack

A metal frame that holds networking equipment.

Ethernet Cable

A copper cable used to connect devices to a wired network.

Fiber Optic Cable

Uses light to transmit data over long distances at very high speeds.

Keystone Jack

A wall or patch panel connector where Ethernet cables terminate.

Public IP Address

An address that can be reached over the Internet.

Private IP Address

An address used only inside local networks.

Subnet Mask

Identifies which part of an IP address is the network and which part is the host.

CIDR (/24, /16)

A shorter way of writing subnet masks.

Default Gateway

Usually the router that sends traffic outside your local network.

Broadcast Address

Sends data to every device on a subnet simultaneously.

DHCP (Dynamic Host Configuration Protocol)

Automatically gives devices an IP address and other network settings.

Lease

The amount of time a device keeps its assigned IP address.

Reservation

Permanently assigns a specific IP address to one device.

Scope

The range of IP addresses DHCP can assign.

Renewal

When a device asks DHCP to extend its lease.

DNS (Domain Name System)

Translates website names into IP addresses.

A Record

Maps a domain name to an IPv4 address.

CNAME

Makes one domain name an alias for another.

MX Record

Specifies which mail server receives email.

nslookup

A command used to query DNS servers.

MAC Address Table

A switch’s list of which MAC addresses are connected to each port.

VLAN (Virtual LAN)

Splits one physical network into multiple separate logical networks.

Access Port

A switch port assigned to one VLAN.

Trunk Port

A switch port that carries traffic for multiple VLANs.

STP (Spanning Tree Protocol)

Prevents loops between switches.

Static Route

A manually configured path to another network.

Dynamic Route

Routes learned automatically using routing protocols.

Default Route

The path used when no specific route exists.

Gateway

The device that forwards traffic to other networks.

SSID

The name of a Wi-Fi network.

WPA2

A common Wi-Fi security standard.

WPA3

A newer and stronger Wi-Fi security standard.

2.4 GHz

Longer range but slower speeds and more interference.

5 GHz

Faster speeds but shorter range.

Wi-Fi 6

A newer wireless standard with better speed and efficiency.

Ping

Tests whether another device can be reached over the network.

tracert / traceroute

Shows the path packets take across the network.

ipconfig

Displays a Windows computer’s IP configuration.

ifconfig

Displays network settings on older Linux and macOS systems.

ip

The modern Linux command for viewing and configuring network interfaces.

arp

Displays the mapping between IP addresses and MAC addresses.

netstat

Shows active network connections and listening ports.

route

Displays or modifies the routing table.

ssh

Securely connects to another computer remotely.

Firewall

Blocks or allows network traffic based on security rules.

VPN (Virtual Private Network)

Creates an encrypted connection between your device and another network.

Antivirus

Detects and removes malicious software.

Malware

Any software designed to damage or compromise computers.

Phishing

A scam that tricks users into revealing sensitive information.

MFA (Multi-Factor Authentication)

Requires two or more methods to verify a user’s identity.

Encryption

Converts readable data into unreadable data to protect it.

ACL (Access Control List)

A list of rules that allows or blocks network traffic.

Device Manager

Displays and manages installed hardware.

Network Adapter

The software interface for a computer’s network card.