Grade 11 ICT – Chapter 3: The Internet & Electronic Mail

🌍 3.1.1 Introduction to the Internet

The Internet is a global collection of interconnected computer networks — the largest and most powerful information-sharing system ever created. It is often called the "Information Super Highway" because of the incredible speed at which data travels around the world.

Thanks to the Internet, the entire world has become a "global village" — people from opposite ends of the Earth can communicate instantly, share knowledge, and access resources as if they were next door.

🏛️ Who Owns the Internet?

The Internet has no single owner! A non-profit organisation called "The Internet Society" oversees the ethics, principles, and protocols that keep it running smoothly.

🖥️ You Are Part of It!

The moment you connect your computer to the Internet, your computer becomes part of the Internet too — you can then access any information on any subject from anywhere in the world.

📡 What Type of Network?

The Internet is a Wide Area Network (WAN) — it spans the entire globe and connects billions of devices. It uses the Client-Server Model for communication.

🖥️ Client–Server Model

Every computer on the Internet falls into one of two roles:

        ⬇️ Downloading — Getting information from the server to your computer. E.g., opening a website, watching a video.
      

        ⬆️ Uploading — Sending information from your computer to the server. E.g., posting a photo, sending an email.
      

Types of Internet Servers

🌐 Web Server

Stores web pages (HTML, images, videos) and delivers them to client computers on request.

📧 Mail Server

Stores incoming electronic mail and routes outgoing emails. Handles all email traffic on the Internet.

🔍 DNS Server

Translates human-friendly domain names (like www.google.com) into machine-readable IP addresses.

📜 Internet Protocols

      What is a Protocol? A protocol is a set of rules that governs how data is transmitted over a network. Think of it like the traffic laws of the Internet — every device must follow the same rules to communicate properly!
    

HTTP

HyperText Transfer Protocol

📄 HTML document exchange

TCP/IP

Transmission Control Protocol / Internet Protocol

🔄 Controls IP address exchange

FTP

File Transfer Protocol

📁 File exchange

SMTP

Simple Mail Transfer Protocol

📧 Electronic mail exchange

ICMP

Internet Control Message Protocol

⚠️ Error messages & control

📌 Key Points — Introduction

The Internet is a worldwide collection of interconnected computer networks
"The Internet Society" manages ethics and protocols — the Internet has no single owner
When you connect to the Internet, your computer becomes part of it
The Internet is a WAN based on the Client–Server model
Downloading = server → client | Uploading = client → server
Protocols (HTTP, TCP/IP, FTP, SMTP, ICMP) are the rules of Internet communication

🔗 3.1.2 Uniform Resource Locator (URL)

The Internet contains an enormous amount of information stored in websites. To uniquely identify any resource (page, image, file) within the World Wide Web, we use a Uniform Resource Locator, or URL.

The protocol used to transmit web information between computers is called HTTP (HyperText Transfer Protocol).

http://www.edupub.gov.lk/e-books/english/ict.pdf

🔒 Protocol: HTTP 🌐 WWW 🏷️ Domain Name 📂 Path 📄 Resource

      ⚠️ Important Rule: A valid URL must contain — at minimum — the protocol (HTTP) and the domain name. The path and resource are optional.
    

Sri Lankan Education URLs

URL	Organisation
`http://www.moe.gov.lk`	Ministry of Education
`http://www.nie.lk`	National Institute of Education
`http://www.doenets.lk`	Department of Examinations
`http://www.edupub.gov.lk`	Educational Publications Department

🔢 3.1.3 IP Addresses

Every computer connected to the Internet must have a unique identity. This identity is called an Internet Protocol (IP) Address.

Dotted Decimal Notation

An IP address consists of four numbers, each ranging from 0 to 255, separated by full stops (dots). This format is called Dotted Decimal Notation.

172

193

213

154

      🏢 Internet Service Provider (ISP)

      IP addresses are assigned by an ISP (Internet Service Provider) — a company that provides access to the Internet. You pay the ISP a fee, and they give you an IP address so you can connect to the Internet.

      📊 IP Address Range: Each of the 4 numbers can be between 0 and 255. This gives us over 4 billion possible unique addresses! (IPv4 format)
    

🏷️ 3.1.4 Domain Names

While IP addresses identify computers, domain names identify websites. Domain names are easier for humans to remember than long strings of numbers.

For example, in the URL http://www.edupub.gov.lk, the domain name is edupub.gov.lk. Here gov = government, lk = Sri Lanka.

Generic Top-Level Domains

Domain	Meaning
.com	Commercial
.org	Non-profitable organisations
.gov	Public
.edu	Education
.net	Web / Network

Country Code	Country
.lk	🇱🇰 Sri Lanka
.in	🇮🇳 India
.au	🇦🇺 Australia
.jp	🇯🇵 Japan
.uk	🇬🇧 United Kingdom
.us	🇺🇸 United States

      📌 Top-Level Domain (TLD) — The domain at the right-most corner of a domain name is called the Top-Level Domain. Example: in edupub.gov.lk, the TLD is .lk
    

URL → Domain Name → TLD Examples

URL	Domain Name	Top-Level Domain
`http://www.google.com`	google.com	.com
`http://www.edupub.gov.lk`	edupub.gov.lk	.lk
`http://www.nie.lk/pages/syllabus.asp`	nie.lk	.lk
`http://www.unicode.org/consortium/consort.html`	unicode.org	.org

🔄 3.1.5 How the Internet Works — DNS

Humans find it hard to remember long numbers like 209.191.122.70. So we use domain names like www.yahoo.com instead. The system that translates domain names into IP addresses is called the Domain Name System (DNS).

6-Step DNS Resolution Process

User opens the browser and types a URL (e.g., http://www.yahoo.com)

Resolver — The browser asks the operating system (OS) to find the IP address for the domain name entered.

DNS Server lookup — The OS queries the DNS server, which translates www.yahoo.com → 209.191.122.70 and returns the IP address.

Browser now has IP — The browser receives the IP address and sends an HTTP GET command to the web server at that IP.

Web server responds — The web server receives the request and sends back an HTML data stream.

Browser renders the page — The browser reads the HTML and displays the web page to the user. All this happens in milliseconds! ⚡

3.1.7 Domain Name Server (DNS)

      What DNS Does: The Domain Name Server (DNS) acts like a phone book for the Internet. It converts easy-to-remember domain names into IP addresses that computers use to find each other.
    

🔍 Interactive URL Analyzer

Type any URL below and break it into its parts instantly!

🌐 3.1.6 Services of the Internet

🌍

World Wide Web

Billions of web pages accessible via browsers

📁

File Transfer (FTP)

Transfer large files between computers

🖥️

Remote Access

Control a computer from a distance

🤝

File Sharing

Share files with many users at once

🎬

Media Streaming

Watch videos & music without downloading

🔎

Search Engines

Find any information on the web

📧

Electronic Mail

Send & receive messages instantly

🌍 3.1.6.1 World Wide Web (WWW)

The World Wide Web (WWW) is a service of the Internet — it is a massive collection of electronic documents (web pages) stored on computers all around the world that are connected to the Internet.

      👨‍💻 Father of the WWW: The World Wide Web was invented by Sir Tim Berners-Lee. He created it in 1989 to help scientists share information more easily.
    

Web Browsers

A Web Browser is an application software used to access and navigate websites. You type a URL in the address bar and press Enter to visit a site.

🔵 Internet Explorer

🦊 Mozilla Firefox

🟡 Google Chrome

🍎 Safari

🎭 Opera

Web Pages & Websites

Term	Definition
Website	A collection of several related web pages under one domain name
Web Page	A single page in a website containing text, images, videos, and hyperlinks
Home Page	The main/first page of a website that contains basic information about the site
Hyperlink	A clickable link that takes you to another page or website instantly
Address Bar	The field in a browser where you type the URL to visit a site

📁 3.1.6.2 File Transfer Protocol (FTP)

Sometimes you need to send or receive very large files — too big for email attachments. That's where FTP (File Transfer Protocol) comes in.

📧 Email Attachment — Small Files

Files of small size can be sent as email attachments. This is suitable for documents, small images, etc.

📁 FTP — Large Files

FTP is used to transfer large files between computers over the Internet. It runs on top of the TCP/IP protocol.

      FTP Uses:
      Upload — Send files from your (client) computer to a server on the Internet
Download — Get files from server computers on the Internet to your computer

    

🖥️ 3.1.6.3 Remote Access

Remote Access allows you to control and operate a computer over the Internet from a different location, as if you were sitting right in front of it.

Functions of Remote Access

💿 Software Installation

Installing software from a server computer onto a client computer remotely — without physically being present.

🔧 Remote Troubleshooting

IT technicians can fix problems on client computers from a remote location — very useful for tech support!

      ⚠️ Danger — Hacking!

      Remote access technology can be misused. Hackers may use it to illegally access and steal important data stored on computers without the owner's knowledge. This illegal act is called hacking. Always protect your devices with strong passwords and firewalls!

🤝 3.1.6.4 File Sharing

The main objective of computer networking is to share resources. File sharing allows many users to access the same file at the same time.

      Real Examples:
      When thousands of students check exam results online at the same time — they are all accessing the same file simultaneously
Millions of users can visit the same website (like Facebook or Google) at the exact same moment

    

🎬 3.1.6.5 Streaming of Media

Media Streaming lets you watch videos or listen to music while it downloads — you don't have to wait for the entire file to finish downloading before you can enjoy it.

User visits web page

Finds a media file (video/audio) they want to watch or hear

Web server requests

Web server sends a message to the streaming media server requesting the file

Streaming server sends

Media server streams the file directly to the user, bypassing the web server

Client decodes & plays

Client software on user's computer decodes and plays the media file

      Internet supports sharing of all types of multimedia: text, images, audio, and video. Downloading songs, images, and videos from the Internet are everyday examples of streaming and file sharing.
    

🔎 3.1.6.6 Search Engines

The Internet has billions of web pages. Without knowing the exact URL of a website, it would be nearly impossible to find information. That's where Search Engines come in — they are specially designed tools that help users find information quickly and easily.

How to Use a Search Engine

Open your web browser and go to a search engine (e.g., www.google.com)

Type your keywords (the topic you want to find) into the search box

Click the Search button (or press Enter)

A list of web pages with hyperlinks appears — click any link to visit that page and get your information

Popular Search Engines

URL	Search Engine
`http://www.google.com`	🔍 Google (world's most popular)
`http://www.yahoo.com`	🟣 Yahoo!
`http://www.ask.com`	❓ Ask
`http://www.msn.com`	🟦 MSN / Bing

📧 3.2.1 Electronic Mail (E-mail)

Electronic Mail (E-mail) enables people to exchange messages and files electronically over the Internet between two or more people. It is considered the cheapest and fastest method of communication in the world!

Several organisations provide free e-mail services through the Internet (Gmail, Yahoo Mail, Hotmail, etc.). The only cost is for using the Internet itself.

✉️ E-mail Address Structure

Every person on the Internet has a unique e-mail address — no two people can have exactly the same one. Let us study the structure:

exams@doenets.lk

👆 Username exams

👆 @ Symbol separates

👆 Domain Name doenets.lk

      E-mail address = username + @ + domain name

      The @ (at) symbol separates the username from the domain name. Both the sender and receiver must have email accounts.

Signing into an Email Account

Before you can send or read emails, you must log into your email account using your username and password, then click "Sign In".

📤 Sending an Email — To, Cc, Bcc

Understanding To, Cc, and Bcc

TO:

The primary recipient(s) of the email. Everyone can see who is in the To field.

Example: sasikala7@gmail.com

CC: (Carbon Copy)

Sends a copy to secondary recipients. All recipients (To and Cc) can see who received the Cc.

Example: bpdasun@yahoo.com

BCC: (Blind Carbon Copy)

Sends a hidden copy. The Bcc recipient can see ALL addresses, but To/Cc recipients cannot see the Bcc address.

Example: monali@sltnet.lk

      📎 Attachment: You can attach files (documents, images, etc.) by clicking the attachment button (paperclip icon). Click "Send" when ready.
    

🎮 Interactive Email Composer

📝 New Message — Practice Composing an Email

To:

Cc:

Bcc:

Subject:

📎 Attachment

📂 Email Folders

Email accounts are organised into folders for easy management:

📥

Inbox

Stores all received emails

📝

Drafts

Emails started but not yet sent

📤

Sent

All emails you have sent

🗑️

Trash / Deleted

Deleted emails kept for a period

🚫

Spam / Junk

Unwanted emails kept out of Inbox

      ⚠️ What is Spam?

      Spam refers to unwanted, unsolicited emails — usually advertisements or scams — that are automatically filtered into a separate Spam/Junk folder so they don't clutter your Inbox.

💬 3.2.2 Instant Messaging (IM)

Instant Messaging (IM) allows two persons to exchange short text messages very fast (chat) over the Internet using the chat facility. Messages appear almost immediately on the recipient's screen.

This is also called chatting — using the chat facility to have real-time text conversations.

Popular Instant Messaging Tools

      How IM Works: A message is typed and sent → the message travels through the Internet → the receiving person sees it instantly on their screen. IM can also support voice calls, video calls, and file sharing.
    

🎥 3.2.3 Video Conferencing

Video Conferencing is the technology that allows two or more people in different locations to have a live, real-time conversation using both audio and video transmitted over computer networks.

      Think of it like a phone call, but you can see each other on screen too! It removes the need for expensive and time-consuming travel for meetings.
    

Requirements for Video Conferencing

💻

Computers

Desktop or laptop with adequate processing power

📷

Web Camera

Captures and sends live video of the user

🌐

Internet Connection

A fast, stable broadband connection is required

🎙️

Communication Software

Software with audiovisual facilities (Zoom, Skype, etc.)

      Applications of Video Conferencing: Business meetings across cities and countries, online classes and education, medical consultations, interviews, and family video calls.
    

👥 3.2.4 Social Networks

Social Networks are online platforms used to maintain social relationships over the Internet. They connect people with shared interests, backgrounds, or social bonds.

What Social Networks Allow You to Do

📸 Share Multimedia

Exchange personal details, photographs, videos, and daily activity updates with friends and family worldwide.

🌏 Widen Social Circles

Connect with new people, join communities, and build relationships that cross geographical boundaries.

⚠️ Potential Issues

Social networks can also create social issues.

Examples of Social Networks

☁️ 3.3 Cloud Computing

Cloud Computing is the practice of using a network of remote servers hosted on the Internet to store, manage, and process data — rather than using a local server or your own personal computer.

Imagine storing all your files, running your software, and doing all your work "in the cloud" (on powerful remote servers) — accessible from any device, anywhere in the world!

🏗️ Main Services of Cloud Computing

IaaS

Infrastructure as a Service

Provides a virtual environment of servers — giving you storage space, firewall, and computing resources through large data centres over the Internet.

      Example: Your company needs server space and a firewall, but you don't have the physical hardware. With IaaS, you can obtain these facilities through cloud computing — even though you do not own them!
    

PaaS

Platform as a Service

Provides a complete server environment for software development — including the operating system, programming language environment, database, and web server.

      Example: You want to develop a web application, but your computer doesn't have the required operating system or compilers installed. With PaaS, you can write and run code directly in the cloud — no local setup needed!
    

SaaS

Software as a Service

Provides ready-to-use software via the cloud without needing to install it on your device. This reduces cost and complexity.

      Example: On Android devices, using Google Docs (word processing) or Google Sheets (spreadsheet) through the web browser — without installing any software on your device!
    

⚖️ Advantages & Disadvantages of Cloud Computing

✅ Advantages

Lower software cost — no need to buy and install software
Improved performance — powerful remote servers do the work
Fewer maintenance issues — the provider handles updates
Instant software updates — always have the latest version

❌ Disadvantages

Requires a constant Internet connection — no offline use
Does not work well on slow Internet connections

📊 Cloud Services Comparison

Feature	IaaS	PaaS	SaaS
What it provides	Virtual hardware & infrastructure	Development platform	Ready-to-use applications
Target users	System administrators, IT teams	Software developers	End users, businesses
Example	Amazon AWS, Microsoft Azure	Google App Engine, Heroku	Gmail, Google Docs, Office 365
You manage	OS, apps, data	Apps and data only	Just the data

📌 Key Points — Cloud Computing

Cloud computing uses remote Internet servers instead of local machines
IaaS = virtual hardware (servers, storage, firewall)
PaaS = development platform (OS, database, compilers)
SaaS = ready software via browser (no installation needed)
Advantage: lower cost, improved performance, fewer maintenance issues, instant updates
Disadvantage: needs constant Internet; does not work well on slow connections

✏️ Activity 1 — Match the Columns (Set A)

Click an item in Column A, then click its matching item in Column B. Match all four pairs!

Column A

e mail address

Domain name

Uniform Resource Locator

IP address

Column B

http://www.nie.lk/syallabus/ol/ict.pdf

172.92.83.106

somasiri@gmail.com

doenets.lk

✏️ Activity 2 — Match the Columns (Set B)

Match each item in Column A with the correct answer in Column B!

Column A

Web address

A service in the Internet

Domain name

Search engine

Column B

Converts domain name into IP addresses

Google

World Wide Web

Mozilla Firefox

🖥️ DNS Resolver Simulator

DNS Resolver — Terminal

DNS Resolver ready. Type a domain name and click Resolve.

🎯 Chapter 3 — Multiple Choice Quiz

Answer all 10 questions, then click "Check My Answers" to see your score and explanations!

Question 1 of 10

What does URL stand for?

Question 2 of 10

An IP address consists of how many numbers separated by dots?

Question 3 of 10

Which protocol is used to exchange HTML documents on the Internet?

Question 4 of 10

In the email address exams@doenets.lk, what does exams represent?

Question 5 of 10

What is the function of the Domain Name Server (DNS)?

Question 6 of 10

Which domain extension is used for non-profitable organisations?

Question 7 of 10

Which cloud computing service provides a virtual environment of servers and storage through large data centres?

Question 8 of 10

What is Bcc in an email?

Question 9 of 10

Who is considered the "Father of the World Wide Web"?

Question 10 of 10

What does SMTP stand for?

0/10

Your Score

Well done!

📋 Complete Chapter Summary

The Internet is a worldwide collection of networks — the "Information Super Highway"
URL uniquely identifies resources on websites (protocol + domain + path + resource)
IP addresses identify each computer — four numbers (0–255) in Dotted Decimal Notation
Domain names identify websites; DNS converts them to IP addresses
The Internet is a WAN based on the Client–Server model
Protocols (HTTP, TCP/IP, FTP, SMTP, ICMP) are the rules of communication
Internet services: WWW, FTP, Remote Access, File Sharing, Streaming, Search Engines, Email
Sir Tim Berners-Lee invented the World Wide Web
Email address = username + @ + domain name; cheapest & fastest communication
To = primary; Cc = visible copy; Bcc = hidden copy
Video conferencing needs: computer, webcam, Internet, audiovisual software
Cloud computing: IaaS (infrastructure), PaaS (platform), SaaS (software)