34  Internet, Intranet, E-Mail and Conferencing

34.1 The Internet — A Network of Networks

The Internet is a global, decentralised network of interconnected networks. Its precursor, ARPANET, was developed by the US Department of Defense in 1969. The Internet grew through universities and research laboratories in the 1980s, became commercial in the 1990s, and now connects billions of devices.

TipKey Internet Milestones
  • 1969 — ARPANET, the first packet-switched network.
  • 1971 — Ray Tomlinson sends the first email; introduces the *** symbol.
  • 1983 — TCP/IP becomes the standard protocol; the modern Internet is born.
  • 1989–1991 — Tim Berners-Lee invents the World Wide Web (WWW) at CERN.
  • 1995 — Internet becomes commercial in India (BSNL).

34.2 Internet vs World Wide Web

TipInternet vs WWW — A Frequent NTA Distractor
Feature Internet WWW
Nature Network of networks Service running on the internet
Components Hardware, cables, satellites, routers Web pages, browsers, hyperlinks
Year 1960s–1980s Tim Berners-Lee, 1989–91
Communication TCP/IP HTTP/HTTPS over TCP/IP

The Internet is older and broader than the WWW. Email, file transfer, and many other services run over the Internet without using the WWW.

34.3 How the Internet Works — Quick Overview

TipWorking Vocabulary
  • IP Address — unique numeric address for every internet-connected device. IPv4 uses 32 bits (4.3 billion addresses); IPv6 uses 128 bits (effectively unlimited).
  • DNS — Domain Name System — translates human-readable names (like google.com) into IP addresses (like 142.250.190.46).
  • HTTP / HTTPS — protocols that browsers use to request web pages from servers.
  • TCP / UDP — transport layer protocols (TCP = reliable; UDP = fast, less reliable).
  • Router — directs packets between networks.
  • ISP — Internet Service Provider — connects you to the internet.

flowchart LR
  U[User<br/>Browser] -->|URL| D[DNS<br/>Lookup]
  D -->|IP address| W[Web Server]
  W -->|HTTP response| U
  U -.->|via| ISP[ISP / Router]
  ISP --> W
    classDef default fill:#003366,color:#ffffff,stroke:#ffcc00,stroke-width:3px,rx:10px,ry:10px;

34.4 Domain Names and Top-Level Domains

TipCommon Top-Level Domains (TLDs)
TLD Purpose Example
.com Commercial google.com
.org Organisations (often non-profit) wikipedia.org
.net Networks ssrn.net
.edu Educational (mainly US) harvard.edu
.gov Government (US) whitehouse.gov
.mil Military af.mil
.int International orgs un.int
.in India (country code) ugc.gov.in
.gov.in Indian Government mygov.in
.ac.in Indian academic institutions iimk.ac.in
.edu.in Indian education aicte-india.edu.in
.io Tech / startups github.io

34.5 Web Browsers and Search Engines

TipBrowser vs Search Engine
  • Browser — the application that displays web pages (Chrome, Firefox, Safari, Edge, Opera, Brave).
  • Search engine — a website that indexes the web and returns matching results (Google, Bing, DuckDuckGo, Yandex, Baidu).

A browser is the vehicle; a search engine is a destination you visit using the vehicle.

34.6 Intranet vs Extranet vs Internet

TipThree Network Layers
Layer Audience Example
Internet Open to the world Public website
Intranet Internal to an organisation Employee portal
Extranet Selected outside parties Vendor / customer portal extension of intranet 

flowchart TB
  I[Internet<br/>Public global network] --> E[Extranet<br/>Internal + selected outsiders]
  E --> N[Intranet<br/>Internal only]
    classDef default fill:#003366,color:#ffffff,stroke:#ffcc00,stroke-width:3px,rx:10px,ry:10px;

34.7 Email — Structure and Protocols

An email address has the form username@domain.tld — for example, vijay@ugc.gov.in. The *** symbol was introduced by Ray Tomlinson in 1971.

TipEmail Protocols
Protocol Function Direction
SMTP Simple Mail Transfer Protocol — sends mail Outgoing
POP3 Post Office Protocol v3 — downloads mail to one device Incoming
IMAP Internet Message Access Protocol — keeps mail on server Incoming, multi-device
MIME Multipurpose Internet Mail Extensions — handles attachments Encoding
S/MIME, PGP Encryption and signing Security
TipPOP3 vs IMAP — A Frequent NTA Distractor
  • POP3 downloads mail and removes it from the server. Best for one-device use.
  • IMAP keeps mail on the server; access from any device. Modern default.
TipEmail Header Components
  • From — sender’s address.
  • To — primary recipient.
  • Cc — carbon copy; visible to all.
  • Bcc — blind carbon copy; hidden from other recipients.
  • Subject — short topic line.
  • Date / Timestamp — when sent.
  • Reply-To — alternate address for replies.
TipEmail Etiquette (Netiquette)
  • Use a clear subject line.
  • Avoid CAPITAL LETTERS (perceived as shouting).
  • Keep replies focused; trim quoted threads.
  • Verify recipients before clicking Send.
  • Avoid ambiguous “Reply All”.
  • Be careful with attachments — large files clog inboxes.

34.8 Web Conferencing

Web conferencing is real-time, two-way communication over the internet, typically with audio, video, screen sharing and chat.

TipMajor Web Conferencing Tools
Tool Owner Notes
Zoom Zoom Video Communications Popular for education and business
Google Meet Google Integrates with Workspace
Microsoft Teams Microsoft Integrates with Microsoft 365
Cisco Webex Cisco Long-standing enterprise tool
Skype Microsoft Pioneer; consumer-grade
Jio Meet Reliance Jio Indian alternative
TipSynchronous vs Asynchronous Communication
  • Synchronous — same-time, real-time (Zoom call, phone, live chat).
  • Asynchronous — different-time (email, recorded video, forum posts).

34.9 VoIP — Voice over IP

VoIP transmits voice as data packets over the internet rather than over the traditional telephone circuit. Examples: WhatsApp call, Skype, Google Voice, Jio4G voice. Most modern phone systems use VoIP at the back end.

34.10 Practice Questions

Q 01 Internet vs WWW Easy

Which of the following statements is correct?

  • AThe Internet and the World Wide Web are the same
  • BThe WWW is a service that runs on the Internet
  • CThe WWW was developed before the Internet
  • DThe Internet runs on the WWW
View solution
Correct Option: B
The Internet is the underlying network. The WWW (Tim Berners-Lee, 1989–91) is one of many services running on the Internet.
Q 02 WWW Inventor Easy

The World Wide Web was invented by:

  • AVint Cerf
  • BTim Berners-Lee
  • CBill Gates
  • DRay Tomlinson
View solution
Correct Option: B
Tim Berners-Lee invented the WWW at CERN (1989–91). Vint Cerf is "father of the Internet"; Tomlinson sent the first email.
Q 03 Email Protocols Medium

SMTP is used for:

  • AReceiving incoming email
  • BSending outgoing email
  • CEncrypting email
  • DBrowsing the web
View solution
Correct Option: B
SMTP = Simple Mail Transfer Protocol — for sending outgoing email. POP3 and IMAP are for receiving.
Q 04 DNS Medium

What does DNS do?

  • ATranslates a domain name to an IP address
  • BEncrypts internet traffic
  • CStores email messages
  • DCompresses files
View solution
Correct Option: A
DNS (Domain Name System) translates human-readable domain names (like google.com) to IP addresses.
Q 05 Network Types Medium

A company's internal network — accessible only to its own employees — is called:

  • AInternet
  • BIntranet
  • CExtranet
  • DDarknet
View solution
Correct Option: B
Intranet = internal-only network. Extranet extends part of the intranet to selected outsiders. Internet is public.
Q 06 First Email Medium

The first email was sent by Ray Tomlinson in:

  • A1965
  • B1971
  • C1983
  • D1991
View solution
Correct Option: B
Ray Tomlinson sent the first email in 1971 and introduced the @ symbol to separate username from host.
Q 07 Email Header Medium

In an email, what does Bcc stand for?

  • ABackup carbon copy
  • BBlind carbon copy
  • CBulk carbon copy
  • DBroadcast carbon copy
View solution
Correct Option: B
Bcc = Blind carbon copy — recipients in Bcc are hidden from each other and from To/Cc recipients.
Q 08 Browser vs Search Engine Easy

Which of the following is a *web browser* (not a search engine)?

  • AGoogle
  • BBing
  • CMozilla Firefox
  • DDuckDuckGo
View solution
Correct Option: C
Firefox is a browser. Google, Bing and DuckDuckGo are search engines you visit via a browser.
ImportantQuick recall
  • ARPANET (1969) → TCP/IP (1983) → WWW (1989–91, Berners-Lee at CERN) → commercial Internet in India (1995).
  • Internet = network of networks; WWW = a service on the Internet.
  • DNS = name → IP. IP: IPv4 (32-bit) and IPv6 (128-bit).
  • Network layers: Internet · Extranet · Intranet.
  • Email protocols: SMTP (send), POP3 (receive, download), IMAP (receive, server-stored), MIME (attachments).
  • Email header: From, To, Cc, Bcc, Subject, Date, Reply-To.
  • Browsers (Chrome, Firefox, Safari, Edge) ≠ Search engines (Google, Bing, DuckDuckGo).
  • @ symbol introduced by Ray Tomlinson, 1971.