Networking

Network Basics

100

Two or more connected devices that share data, resources, and communication rules form this.

network

200

This is the largest global “network of networks.”

Internet

300

A private network used by employees inside an organization is called this.

intranet

400

A network covering one building, home, school, or campus is classified as this type.

LAN

500

This method divides data into smaller pieces that can travel through different routes before being reassembled.

packet switching

OSI & Devices

100

This OSI layer handles cables, radio signals, light pulses, and raw bits.

Physical layer

200

A switch mainly operates at this OSI layer and forwards data using MAC addresses.

Layer 2, the Data Link layer

300

A router operates mainly at this OSI layer and forwards packets using IP addresses.

Layer 3, the Network layer

400

TCP, UDP, and port numbers belong to this OSI layer.

Layer 4, the Transport layer

500

HTTP and DNS belong to this top OSI layer, where users interact with network services.

Layer 7, the Application layer

Addresses & Ports

100

This hardware address identifies a network interface on the local network.

MAC address

200

This logical address allows a device to communicate across different networks.

IP address

300

In the building-and-room analogy, the IP address is the building and this is the room.

port number

400

Websites using HTTPS normally communicate through this port.

port 443

500

The slash-number in an address such as 192.168.1.0/24 uses this notation to show how many bits belong to the network portion.

CIDR

TCP, UDP & DNS

100

This transport protocol is reliable, ordered, and resends lost information.

TCP

200

This fast, connectionless protocol is commonly used for live video, voice calls, and online gaming.

UDP

300

SYN, SYN-ACK, and ACK are the three steps in this process.

TCP three-way handshake

400

This system translates a domain name such as google.com into an IP address.

DNS

500

This DNS feature temporarily stores an answer so that it does not need to be looked up again immediately.

DNS caching

Network Security

100

This security system allows or blocks network traffic based on rules.

firewall

200

This creates an encrypted connection between a device and another network over the Internet.

VPN

300

This server sits in front of other servers, hides them, and can distribute incoming requests.

reverse proxy

400

This globally distributed system stores copies of website content closer to users.

CDN

500

Unlike a Layer 4 firewall that sees only IP addresses and ports, this firewall can inspect a full HTTP request and block attacks such as path traversal.

Layer 7 firewall or Web
Application Firewall (WAF)