The Internet, DNS, and Hosting

This lesson covers the internet, the Domain Name System (DNS), and web hosting, as required by OCR J277 Section 1.3.2. You need to understand how the internet works and how websites are made accessible to users.

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What Is the Internet?

The internet is a global network of networks — a vast WAN (Wide Area Network) that connects billions of devices worldwide. It uses standardised protocols (agreed rules) to allow different networks and devices to communicate.

Key Points About the Internet

Feature	Detail
Type	The world's largest WAN
Structure	A network of networks — LANs and WANs interconnected via routers
Infrastructure	Fibre optic cables (including undersea), satellites, telephone lines, mobile networks
Protocols	Uses TCP/IP as its fundamental communication protocol
Ownership	No single organisation owns the internet; it is maintained by ISPs and international bodies

The Internet vs The World Wide Web

These terms are often confused but mean different things:

Term	What It Is
The Internet	The physical network infrastructure (cables, routers, servers) that connects devices globally
The World Wide Web (WWW)	A collection of websites and web pages accessed via the internet using web browsers and HTTP/HTTPS

The web is a service that runs on the internet. Other services that use the internet include email (SMTP/IMAP), file transfer (FTP), and video streaming.

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IP Addresses

Every device connected to the internet has an IP (Internet Protocol) address — a unique numerical address that identifies it on the network.

IPv4

Feature	Detail
Format	Four numbers separated by dots (e.g. 192.168.1.1)
Each number	0-255 (8 bits each, 32 bits total)
Total addresses	Approximately 4.3 billion (2^32)
Problem	Running out of addresses due to the number of devices online

IPv6

Feature	Detail
Format	Eight groups of hexadecimal digits (e.g. 2001:0db8:85a3:0000:0000:8a2e:0370:7334)
Total addresses	Approximately 3.4 x 10^38 (2^128) — virtually unlimited
Adoption	Gradually being adopted to replace IPv4

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DNS (Domain Name System)

The DNS is a system that translates domain names (human-readable addresses like www.google.com) into IP addresses (machine-readable addresses like 142.250.187.46).

Why Is DNS Needed?

Humans find it easier to remember domain names (e.g. www.bbc.co.uk) than IP addresses (e.g. 151.101.0.81). DNS acts as the internet's phone book, looking up the IP address associated with a domain name.

How DNS Works