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  "path": "/posts/how-the-internet-works/",
  "publishedAt": "2026-02-11T04:58:38.593Z",
  "site": "https://karthikkadambi.com",
  "tags": [
    "DHCP",
    "IP Address",
    "IPv6",
    "ARP (Address Resolution Protocol)",
    "MAC Address",
    "NAT (Network Address Translation)",
    "Subnet",
    "Packets",
    "Port",
    "TCP/IP",
    "UDP",
    "DNS (Domain Name System)",
    "Domain Name Registration",
    "TCP/IP",
    "SSL/TLS",
    "HTTPS",
    "HTTP/3& QUIC",
    "Switching",
    "Routing",
    "BGP (Border Gateway Protocol)",
    "CDN (Content Delivery Network)",
    "Cache",
    "Firewall",
    "WAF (Web Application Firewall)",
    "VPN",
    "Proxy Server",
    "Load Balancer",
    "Hosting",
    "HTTP",
    "WebSockets",
    "Data Communication",
    "Networking",
    "Communication"
  ],
  "textContent": "The internet isn't a single thing, it's a series of handshakes, lookups, and translations that happen in milliseconds. Let's trace a single request from your keyboard to a database halfway across the world.\n\nMost of us take it for granted: you type a URL, hit enter, and a fraction of a second later, a world of information appears. But between that keystroke and the rendered page lies a complex, multi-layered choreography of protocols and hardware.\n\nThis post deconstructs that journey. We'll follow a single request as it exits your browser, traverses your home Wi-Fi, navigates the sprawling infrastructure of your ISP, and finally reaches the \"edge\" and data centers that host the modern web. Every step from local ARP lookups to global BGP routing plays a vital role in the mosaic of global communication.\n\n### Phase 1: The Local Network (LAN)\n\nThe journey begins on your device before you even touch the \"real\" internet.\n\n  1. **Identity & Configuration**: Your computer needs an address. It uses **DHCP** to automatically lease an **IP Address** (or an **IPv6** address) from your router.\n  2. **Hardware Handshakes** : To talk to your router, your computer needs to find its physical hardware address using **ARP (Address Resolution Protocol)** to map the IP to a **MAC Address**.\n  3. **Local Gateway** : Your request hits the router. Because your home uses private IPs, the router uses **NAT (Network Address Translation)** to \"cloak\" your device. The router also manages your local **Subnet** , ensuring that traffic meant for your printer doesn't leak out to the internet and that your internal home network is logically divided.\n  4. **The Exit** : The data is chopped into **Packets** , which are sent out through a specific **Port**. Depending on the application, it will use either **TCP/IP** for reliability or **UDP** for raw speed (common in gaming, video calls, or DNS). These packets travel onto the ISP's fiber lines.\n\n\n\n### Phase 2: The Core Internet (WAN)\n\nNow your request is in the \"wild,\" traveling across the global backbone.\n\n  5. **Finding the Destination** : Your browser doesn't know where `google.com` is. It performs a **DNS (Domain Name System)** lookup. If the domain was recently bought, it might still be propagating through **Domain Name Registration** servers.\n  6. **Establishing Trust** : Once the IP is found, your browser starts a **TCP/IP** handshake. To make it secure, it layers on **SSL/TLS** to create an **HTTPS** connection. If it's a modern site, it might use **HTTP/3& QUIC** to bypass TCP's speed limits.\n  7. **Global Routing** : Your packets don't take a straight line. They are moved by **Switching** and **Routing** equipment. The global path is determined by **BGP (Border Gateway Protocol)** , which acts as the internet's GPS, navigating through different Autonomous Systems.\n\n\n\n### Phase 3: The Edge & Security\n\nBefore reaching the server, the request is inspected and optimized.\n\n  8. **The Front Line** : Most big sites use a **CDN (Content Delivery Network)**. If the content is already in the **Cache** at an edge server near you, the journey ends here—saving thousands of miles of travel.\n  9. **The Gatekeeper** : If not cached, the request hits a **Firewall** and possibly a **WAF (Web Application Firewall)** to check for malicious patterns.\n  10. **The Anonymizer** : If you are using a **VPN** or a **Proxy Server** , your request is further encapsulated or forwarded to hide your original location and identity.\n\n\n\n### Phase 4: The Data Center\n\nThe request has finally arrived at the destination's home.\n\n  11. **The Traffic Cop** : A **Load Balancer** receives the request and decides which specific server in the data center is least busy and should handle it.\n  12. **The Web Server** : The request hits a program like Nginx or Apache (**Hosting**). It interprets the **HTTP** headers.\n  13. **Real-Time Data** : If the page needs live updates (like a chat or stock price), it might upgrade the connection to **WebSockets** for a persistent two-way pipe.\n  14. **Communication & Response**: The server processes the request (often involving **Data Communication** with internal databases) and sends a response packet back through the same layers of the **Networking** stack.\n\n\n\n### How it all connects\n\nThis entire process—from ARP at home to BGP in the core to Load Balancing in the cloud—is what defines modern **Communication**. Every note in this collection is a tile in the mosaic of the global internet.",
  "title": "How Internet Works | Connecting the Dots",
  "updatedAt": "2026-02-08T00:00:00.000Z"
}