Internet Basics Questions for SBI PO

What is the Internet

The Internet is a global network of interconnected computers that communicate using a standard set of rules called protocols. Think of it as the world's largest highway system where data travels as packets from one computer to another. The Internet is not owned by any single organization. The World Wide Web (WWW) is a service that runs ON the Internet — it is a collection of websites and web pages accessed through browsers. Remember: Internet is the infrastructure, Web is just one service on it.

• Internet = global network of networks using TCP/IP protocol
• WWW is a subset of the Internet, not the Internet itself
• Invented by ARPANET in 1969 (US military project); Tim Berners-Lee invented WWW in 1989
• Internet uses packet switching to transfer data
• ICANN (Internet Corporation for Assigned Names and Numbers) manages domain names globally

Key Internet Protocols

Protocols are agreed rules for communication. TCP/IP is the backbone of the Internet. TCP (Transmission Control Protocol) breaks data into packets and ensures they reach correctly. IP (Internet Protocol) handles addressing and routing. Other important protocols each handle a specific job — think of them as specialists in a hospital.

• HTTP (HyperText Transfer Protocol) — transfers web pages; port 80
• HTTPS — secure version of HTTP using SSL/TLS encryption; port 443
• FTP (File Transfer Protocol) — transfers files; port 21
• SMTP (Simple Mail Transfer Protocol) — sends emails; port 25
• POP3 (Post Office Protocol v3) — receives/downloads email; port 110
• IMAP (Internet Message Access Protocol) — reads email from server without downloading; port 143

IP Address and DNS

Every device on the Internet has a unique IP address — like a postal address for computers. IPv4 addresses have 4 sets of numbers (e.g., 192.168.1.1), while IPv6 is the newer longer format to handle address exhaustion. DNS (Domain Name System) is the Internet's phonebook — it converts human-readable domain names like www.sbi.co.in into machine-readable IP addresses. Without DNS, you would need to type numeric IP addresses to visit every website.

• IPv4: 32-bit address, allows about 4.3 billion unique addresses
• IPv6: 128-bit address, virtually unlimited addresses
• DNS converts domain names to IP addresses
• URL (Uniform Resource Locator) is the full web address: protocol + domain + path
• Domain extensions: .com (commercial), .gov (government), .edu (education), .in (India)

Types of Internet Connections

Internet can reach users through several technologies. Dial-up was the oldest and slowest (uses telephone line). Broadband is the modern standard — it covers DSL, Cable, Fiber Optic, and Satellite connections. Mobile internet uses 3G/4G/5G standards. Understanding the speed hierarchy and technology used is a common exam question.

• Dial-up: slowest, uses telephone line, max 56 Kbps
• DSL (Digital Subscriber Line): uses telephone wires but much faster than dial-up
• Cable Internet: uses cable TV lines, faster than DSL
• Fiber Optic: uses light signals, fastest wired connection
• Wi-Fi: wireless local area network using radio waves
• 5G: latest mobile internet standard, very high speed

Web Browsers and Search Engines

A web browser is software used to access and display websites. A search engine is a website that helps you find other websites. These two are often confused in exams. Google Chrome, Firefox, Safari, Edge, and Opera are browsers. Google, Bing, DuckDuckGo, and Yahoo are search engines. A browser is the vehicle; a search engine is a map.

• Browser renders HTML and displays web pages
• URL bar is where you type web addresses in a browser
• Cookies are small files stored by websites on your computer for remembering preferences
• Cache stores temporary web data to speed up future visits
• ISP (Internet Service Provider) is the company that gives you internet access (e.g., Jio, Airtel)

Email and Internet Security Basics

Email (Electronic Mail) is one of the oldest Internet services. SMTP is used to send emails and POP3/IMAP are used to receive them. Internet security is increasingly tested in SBI PO. Know the difference between a virus (self-replicates), worm (spreads across networks without host file), trojan (disguises as legitimate software), and phishing (fake websites/emails to steal data).

• SMTP sends, POP3 and IMAP receive emails
• Firewall filters incoming and outgoing network traffic
• VPN (Virtual Private Network) creates a secure tunnel over the internet
• SSL/TLS: protocols that encrypt data for secure transmission (HTTPS uses this)
• Phishing attacks trick users into revealing passwords via fake emails or websites

• Confusing the Internet with the World Wide Web — WWW is a service on the Internet, not the Internet itself
• Mixing up SMTP, POP3, and IMAP — remember SMTP Sends, POP3 and IMAP receive; IMAP keeps mail on server while POP3 downloads and often deletes from server
• Thinking a browser and a search engine are the same — Chrome is a browser, Google is a search engine that runs inside the browser
• Getting confused between IPv4 (32-bit) and IPv6 (128-bit) — aspirants often reverse the bit counts
• Confusing virus and worm — a worm spreads on its own across networks without needing a host file, a virus needs a host program to attach to

• SMTP Sends, POP3 and IMAP receive — mnemonic: Send Mail To People, People Open Inbox
• Port numbers trick: HTTP=80, HTTPS=443, FTP=21, SMTP=25 — remember '80 for plain, 443 for safe' and FTP at 21 like the age of adulthood
• DNS = Internet Phonebook — just as a phonebook turns names into phone numbers, DNS turns domain names into IP addresses
• WWW vs Internet analogy: Internet is the roads, WWW is just one type of vehicle (car) running on those roads — emails, FTP are other vehicles

• SBI PO frequently asks 1-line definition type MCQs on protocols and their port numbers — memorize the port number table as a whole unit
• Questions on full forms are very common: URL, ISP, DNS, IMAP, VPN, SSL — expect at least one direct full-form question
• Distinction between browser and search engine appears almost every year — do not skip this
• Security-related terms (phishing, firewall, VPN, malware types) have increased in frequency in recent SBI PO papers — treat this as a high-priority subtopic
• Time management tip: Computer Awareness questions are among the fastest to solve — aim to finish each question in under 30 seconds; do not overthink protocol definitions