How the internet works: IP addresses, DNS and packets
Learn what happens when you open a website, from DNS lookups to packets and HTTPS, in plain English.
KS3GCSEMiddle SchoolHigh SchoolCurriculum fit: KS3 and GCSE Computing (networks and the internet in the National Curriculum computing programmes of study). US: no US standards source is linked here: check your school's computer science curriculum.
On this page
What is it?
The internet is a global network of networks that connects billions of devices. Information travels between devices as small chunks of data called packets, which can take different routes and are reassembled at the destination.
The web is a service that runs on the internet. When you visit a website, your browser asks a server for a page using agreed rules called protocols.
Key formulas and ideas
- IP address: a number that identifies a device on a network.
- DNS (Domain Name System): translates names such as example.com into IP addresses.
- Packets: a message is split into numbered packets that are reassembled in order.
- HTTP is the protocol for web pages; HTTPS adds encryption to protect data in transit.
Worked examples
Example 1: Visit a website
Question: Describe what happens when you type a web address into a browser.
- The browser asks a DNS server for the IP address of the site.
- It connects to the server at that address and requests the page using HTTP or HTTPS.
- The server sends the page back in packets, and the browser displays it.
Answer: DNS lookup, connection, request, then packets return the page
Example 2: Packets
Question: A 3000-byte message is sent in packets of at most 1000 bytes. How many packets are needed?
- 3000 ÷ 1000 = 3.
- Each packet is numbered so they can be reassembled in order.
Answer: 3 packets
Example 3: HTTPS
Question: Why is HTTPS better than HTTP for online banking?
- HTTPS encrypts the data sent between your browser and the website.
- Anyone intercepting it cannot easily read it.
Answer: It encrypts the data, protecting it from eavesdroppers
Common mistakes
- Saying the internet and the web are the same thing.
- Thinking a whole message travels as one piece.
- Believing that a padlock means a website is trustworthy. It only means the connection is encrypted.
- Confusing DNS with a search engine.
Practice questions
Frequently asked questions
Is the web the same as the internet?
No. The internet is the global network. The web is a service that runs on it, made of websites and pages.
Is the web the same as the internet?
No. The internet is the global network. The web is a service made of pages and sites that runs on it.
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Reviewed by StudyMorrow editorial review on 5 Nov 2026.