Every time you open a website, dozens of invisible steps happen in under a second. By the end of this page you will be able to explain the whole journey of a single click: how your computer finds the website, how your data travels across the world, and what HTTPS actually protects. No networking experience is needed — we will use everyday analogies.
The internet works like a restaurant. Your computer is the customer: it places an order. The machine that holds the website is the kitchen: it prepares the answer. Your browser (the client) sends a request; the web server answers with the page. Almost everything on the internet follows this pattern.
Every device needs an address, just like a house needs a street address. This is its IP address — for example 93.184.216.34 (IPv4) or the longer 2606:2800:220:1:248:1893:25c8:1946 (IPv6).
But a single server hosts many services at once. That is why we also need a port, which is like an apartment number inside the building:
80 → unencrypted web traffic (HTTP)443 → encrypted web traffic (HTTPS)An address plus a port — 93.184.216.34:443 — points to one specific service, not just one machine.
Computers talk in numbers, but people remember names. The Domain Name System (DNS) is the phone book: it translates example.com into an IP address. When you type a URL, your computer first asks a DNS resolver, “what is the IP address of this domain?” and only then connects to that address.
sequenceDiagram
participant C as Your computer
participant R as DNS resolver
participant D as DNS servers
participant S as Web server
C->>R: What is the IP of example.com?
R->>D: Query example.com
D-->>R: Answer: 93.184.216.34
R-->>C: Answer: 93.184.216.34
C->>S: Connect to 93.184.216.34:443
S-->>C: Welcome!
Data does not travel as one continuous stream. Imagine writing a long letter: you cut it into numbered pages, put each page into its own envelope with the same sender and recipient addresses, and mail them separately. These envelopes are packets. Each packet carries the source address, the destination address, and a piece of the data.
Routers are the post offices in between. Each router only needs to know roughly where to send the packet next; it does not need to know the whole route. At the destination, the packets are put back in order.
flowchart LR
A[Your computer] --> B[Home router]
B --> C[Your ISP]
C --> D[Backbone routers]
D --> E[Server's datacenter]
E --> F[Web server]
Two common ways to send those envelopes:
| TCP | UDP | |
|---|---|---|
| Guarantee | Delivery, order, resend if lost | None |
| Analogy | Registered mail with a receipt | Postcards thrown into the mail |
| Used by | Web pages, email, file transfers | Video calls, games, DNS queries |
HTTP is the language clients and servers speak: GET /index.html asks for a page. But HTTP is like a postcard — anyone who handles it can read it.
HTTPS puts the HTTP message inside a sealed envelope (TLS encryption). Intermediaries can no longer read the contents.
However, a sealed envelope still shows its outside. A network observer can still see:
flowchart LR
subgraph client[Your computer]
A[HTTP request]
end
subgraph wire[On the wire - visible]
B[Destination IP and port]
C[SNI: example.com]
D[Encrypted content - unreadable]
end
subgraph server[Web server]
E[Decrypts and reads the request]
end
A --> B --> C --> D --> E
sequenceDiagram
participant B as Browser
participant R as DNS resolver
participant S as Web server
B->>R: 1. What is the IP of example.com?
R-->>B: 2. 93.184.216.34
B->>S: 3. TCP connection to :443
S-->>B: 4. Connection established
B->>S: 5. TLS handshake (SNI: example.com)
S-->>B: 6. TLS established - now encrypted
B->>S: 7. GET /index.html (encrypted)
S-->>B: 8. Page content (encrypted)
This journey — DNS lookup, connection setup, encryption, then the actual request — is exactly what the next page examines from the firewall’s point of view.
How the Great Firewall Works — where and how this journey can be blocked.