Internet Basics

The internet is a worldwide network of computers that can send data to each other. When Priya in Jaipur opens her college result page, pays a bill with UPI, or video-calls her brother in Bengaluru, her phone or computer is exchanging small pieces of data with other computers, often thousands of kilometres away, in under a second.

In this lesson you will learn how you connect to the internet, what happens when you open a website, how to read a web address, and what the little padlock in the browser really means.

How you connect

You reach the internet through an Internet Service Provider (ISP): a company that sells internet access, such as a mobile network or a broadband company.

Wi-Fi is not the internet itself. It is a short-range wireless link to a router, and the router connects to the internet through the ISP. If the Wi-Fi icon shows "connected" but no website opens, the problem is often the router or the ISP, not your computer.

Connect a laptop to Wi-Fi

1. Click the network icon at the right end of the taskbar (or press Windows key + A).
2. Click the arrow next to the Wi-Fi button to see the networks nearby.
3. Click your network's name and click Connect. Tick Connect automatically for your home network.
4. Type the Wi-Fi password (usually printed on a sticker on the router) and click Next.

To use your phone's data instead, turn on Mobile hotspot in the phone's settings, then connect to the phone's name from the laptop in the same way.

The internet and the web are not the same

The World Wide Web (the web) is one service that runs on the internet: websites you open in a browser. Many other services also use the internet without being "websites": email, WhatsApp, UPI payments, video calls, online games and app updates. So "the internet" is the road network, and the web is one kind of vehicle using those roads.

Servers, IP addresses and DNS

A website lives on a server, a computer that is always on and waiting for requests. Your computer is the client: it asks, and the server answers.

Every device on the internet has an IP address, a number used to find it, a bit like a phone number. People cannot remember numbers like 142.251.155.119, so we use names like www.google.com. The DNS (Domain Name System) works like the contacts list on your phone: you choose a name, and DNS finds the number.

You can ask DNS yourself from Terminal:

Resolve-DnsName www.google.com -Type A

Name           Type TTL Section IPAddress
----           ---- --- ------- ---------
www.google.com A    198 Answer  142.251.154.119
www.google.com A    198 Answer  142.251.156.119

Big websites have many servers and several IP addresses, so your numbers will differ.

The ping command checks whether a server answers and how long the round trip takes, in milliseconds (thousandths of a second):

ping -n 2 www.google.com

Pinging www.google.com [142.251.155.119] with 32 bytes of data:
Reply from 142.251.155.119: bytes=32 time=8ms TTL=119
Reply from 142.251.155.119: bytes=32 time=7ms TTL=119

Ping statistics for 142.251.155.119:
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 7ms, Maximum = 8ms, Average = 7ms

Replies mean your internet is working. "Request timed out" or "could not find host" points to a connection problem; Fixing Common Problems shows what to try.

What happens when you open a website

When you type an address and press Enter, the browser sends a short request to the server, written in a language called HTTP. It looks roughly like this:

GET /results HTTP/1.1
Host: www.example.com

It means: "Please give me the page called /results from the website www.example.com." The server sends back a response that starts with a status line, followed by the page itself:

HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8

200 OK means "here it is". You may have seen 404 Not Found, which means the page does not exist at that address. The page content is written in HTML; if you are curious, the HTML tutorial explains it.

Reading a web address (URL)

A URL is the full address of a page. Take this one:

https://www.irctc.co.in/nget/train-search

The most important part is the domain, and especially its last part. Read it from the right: irctc.co.in belongs to IRCTC. A fake site might use irctc-booking-help.in or irctc.co.in.refund-desk.com; in the second one, the real owner is refund-desk.com, because that is what comes last.

Indian government websites usually end in .gov.in or .nic.in, for example india.gov.in. Banks and companies use their own domains, so check the exact spelling.

HTTPS and the padlock

HTTPS means the connection between your browser and the website is encrypted: anyone in between, such as someone on the same public Wi-Fi, cannot read what you send. Browsers show this with a padlock or a small settings icon next to the address. Click it to see Connection is secure.

But HTTPS only protects the connection. It does not prove the website is honest. Fake shopping and fake bank sites also use HTTPS. Always check the domain name as well.

Common mistakes

• Thinking "connected to Wi-Fi" means "connected to the internet". The router might have lost its internet link; restart it.
• Trusting the padlock alone. HTTPS means encrypted, not genuine.
• Reading the domain from the left. The owner is the part just before the ending (.in, .com) on the right.
• Using public Wi-Fi for payments. Switch to mobile data.

Key points

• The internet is a worldwide network; an ISP connects you through mobile data, broadband, Wi-Fi or a hotspot.
• The web (websites) is one service on the internet; email, UPI and video calls are others.
• DNS turns names like www.google.com into IP addresses; ping checks if a server answers.
• A URL has a protocol, a domain and a path; read the domain from the right to find the real owner.
• HTTPS encrypts the connection but does not prove a site is genuine.

ping -n 2 www.irctc.co.in