Internet Fundamentals

How the internet works: from HTTP to DNS, browsers to cloud — the essential concepts for developers.

The Internet

A global network of interconnected computers that enables communication and data exchange across the world. It's built on standardized protocols and decentralized infrastructure.

Learn more (Wikipedia)

HTTP & HTTPS

HTTP (Hypertext Transfer Protocol) is the foundation of data communication on the Web. HTTPS adds a layer of security using TLS/SSL encryption — essential for protecting sensitive data like passwords or payments.

HTTP HTTPS What is SSL/TLS?

Web Browsers

Applications that retrieve, render, and navigate web content. Modern browsers also include developer tools for debugging and performance analysis.

Chrome Firefox Brave Tor

Domain Names & DNS

A domain name (e.g., vulehuan.com) is a human-readable address. DNS (Domain Name System) translates domains into IP addresses (e.g., 192.0.2.1) so browsers can locate servers.

Domain Registrars

Namecheap Cloudflare Unstoppable P.A Vietnam

Public DNS Resolvers

Google DNS Cloudflare OpenDNS

Server & Client

A server provides resources (files, databases, APIs); a client (e.g., browser) consumes them. Most web interactions follow this model.

Web Hosting & Cloud

Hosting rents server space to store your website. Cloud providers offer scalable infrastructure (compute, storage, databases) on demand.

vHost DigitalOcean Vultr AWS Google Cloud Azure

SaaS & Intranet

SaaS (Software as a Service) delivers applications over the internet (e.g., Gmail). Intranet is a private internal network for organizations.

Office 365 Google Workspace Confluence SharePoint

Email

Electronic mail for sending text, files, and media over the internet. Modern services often include encryption and spam filtering.

Gmail ProtonMail Skiff Outlook

VPN (Virtual Private Network)

Encrypts your internet traffic and hides your IP address, enhancing privacy — especially on public Wi-Fi.

NordVPN Surfshark OpenVPN

CDN (Content Delivery Network)

A geographically distributed network of proxy servers that deliver content (HTML, JS, CSS, images) faster to users worldwide.

Cloudflare cdnjs jsDelivr Google Libraries

AI Assistants on the Web

Modern browsers integrate AI tools for summarization, coding help, and content analysis — all powered by your browsing context.

ChatGPT Claude Gemini Bing AI

Key Concepts

Client–Server Model
IP Address vs Domain Name
HTTP Request/Response Cycle
TLS Handshake (HTTPS)
Stateless Protocol (HTTP)
Latency vs Bandwidth

HTTP Request Flow

# 1. DNS lookup vulehuan.com ➜ 104.21.43.78 # 2. TCP handshake Client ─SYN─► Server Client ◄─ACK─ Server Client ─ACK─► Server # 3. TLS (HTTPS only) Client <─ TLS Handshake ─> Server # 4. HTTP request GET / HTTP/1.1 Host: vulehuan.com # 5. HTTP response HTTP/1.1 200 OK Content-Type: text/html <!DOCTYPE html>...