Internet Basics for SBI PO — Protocols, URLs, Email, and Cyber Security

beginner 18 min read

Concept

The internet is a global network of interconnected computers that communicate using a standardised set of rules called protocols. Think of it like the postal system: just as the postal system has addresses, delivery rules, and specialised services (courier for urgent parcels, registered post for valuables), the internet has URLs as addresses, protocols as delivery rules, and specialised services like email, file transfer, and secure transactions.

Here is the mental model that will serve you in the exam hall: every internet action maps to a specific protocol. You type an address (URL) into a browser, the browser uses HTTP or HTTPS to fetch the page, your email client uses SMTP to send mail and POP3/IMAP to receive it, and when you download a file, FTP does the heavy lifting. Each protocol has a designated port number — a door number on the server through which that specific type of traffic enters.

The World Wide Web (WWW) is not the same as the internet — it is one service that runs on top of the internet, specifically the collection of web pages and websites you access through a browser. Other internet services include email, file transfer, VoIP, and online gaming. This distinction — internet as the infrastructure, WWW as a service on it — is a favourite trick question.

An ISP (Internet Service Provider) is the company that physically connects you to this global network. In India, Airtel, Jio, and BSNL are ISPs. Without an ISP, your device has no path into the internet, regardless of what software you have installed.

Security on the internet is layered: HTTPS adds encryption over HTTP, and the encryption itself is done using SSL/TLS protocols. A padlock in your browser's address bar means the connection is using HTTPS with a valid SSL/TLS certificate. This matters for banking — SBI's own netbanking portal uses HTTPS for precisely this reason.


Deep Dive

URL Structure

A Uniform Resource Locator (URL) is the complete address of a resource on the internet. Break down https://www.sbi.co.in/careers/index.html:

| Part | Example | Role | |---|---|---| | Protocol | https:// | How to fetch | | Subdomain | www | Which server section | | Domain name | sbi.co.in | Which organisation | | Path | /careers/index.html | Which specific file |

The exam will test the full form (Uniform Resource Locator — not Universal) and the components. The domain name is the human-readable address; under the hood it maps to a numeric IP address via DNS (Domain Name System).

Protocols and Their Jobs

This table is the single most-tested fact cluster in internet basics:

| Protocol | Full Form | Purpose | Default Port | |---|---|---|---| | HTTP | HyperText Transfer Protocol | Web page transfer | 80 | | HTTPS | HTTP Secure | Encrypted web transfer | 443 | | FTP | File Transfer Protocol | File upload/download | 21 | | SMTP | Simple Mail Transfer Protocol | Sending email | 25 | | POP3 | Post Office Protocol v3 | Receiving email (downloads) | 110 | | IMAP | Internet Message Access Protocol | Receiving email (server-side) | 143 | | DNS | Domain Name System | Domain-to-IP translation | 53 | | DHCP | Dynamic Host Configuration Protocol | Auto IP assignment | 67/68 |

Three ports are frequently tested: 80 (HTTP), 443 (HTTPS), 21 (FTP). Port 25 for SMTP appears occasionally. The rest are rarely tested at SBI PO level.

Email Architecture

An email address has the form username@domain.com. The part after the @ is the domain name, which identifies the mail server — specifically, it tells other mail servers where to deliver the message. The username is just the mailbox label on that server.

The journey of one email:

  1. You compose and click Send — your client uses SMTP to push it to your outgoing mail server.
  2. Your server does a DNS lookup on the recipient's domain to find their mail server.
  3. Your server uses SMTP again to relay the message to the recipient's server.
  4. The recipient's client fetches it using POP3 (downloads and usually deletes from server) or IMAP (reads from server, keeps a copy there).

HTTPS and SSL/TLS

HTTP sends data as plain text — anyone intercepting the packets can read them. HTTPS wraps HTTP inside SSL/TLS encryption, which does two things:

SSL (Secure Sockets Layer) is the older standard; TLS (Transport Layer Security) replaced it and is what modern systems actually use. But the term "SSL certificate" stuck in common usage — so when you see "SSL/TLS" in an option, treat them as synonyms for the exam.

Cookies

Cookies are small text files that a website stores on your device through your browser. They are not passwords, not malware, and they do not speed up your connection. Their purpose: remember who you are across pages and sessions — your login status, language preference, shopping cart contents. Session cookies expire when you close the browser; persistent cookies survive across sessions.

Search Engines vs Browsers

A browser (Chrome, Firefox, Edge) is the software that renders web pages. A search engine (Google, Bing, DuckDuckGo) is a website/service that indexes the web and returns results for queries. You use a browser to access a search engine. These are not interchangeable terms — the exam sometimes offers them as options hoping you confuse them.


Memory Tricks & Shortcuts

patternPort Number Grid: 80-443-21-25

Group the four key ports as a two-row pattern:

  • Web traffic: 80 (HTTP) → 443 (HTTPS) — think 80 is insecure, 443 is secure, both are "web"
  • Transfer/Mail: 21 (FTP) → 25 (SMTP) — both start with "2", FTP is smaller number (files first, then mail)

When you see a port-number question, mentally recite: "web 80/443, file 21, mail 25." Standard approach (reading all options carefully): 20-25 seconds. With this pattern recalled instantly: 5 seconds.

eliminationProtocol-to-Job Mapping: SAFE

Use the acronym SAFE to remember the four most-tested protocols and eliminate wrong options:

  • S — SMTP: Sending mail
  • A — (H)HTTPS: Authentication + encryption
  • F — FTP: File transfer
  • E — Email receiving = POP3/IMAP

When a question asks "which protocol does X", eliminate everything not in SAFE first. This reduces a 4-option question to a 2-option question in under 3 seconds — standard reading: ~15 seconds of deliberation eliminated.

patternURL Full Form: Never Universal, Always Uniform

The trap is "Universal Resource Locator" vs "Uniform Resource Locator." Remember: URLs are standardised — the word for standardised is Uniform. The same logic applies: USB = Universal Serial Bus (hardware that connects anything), URL = Uniform Resource Locator (standardised format). Contrast them — USB is Universal because it connects diverse devices; URL is Uniform because it follows a fixed format. This pairing saves you from the most common URL full-form trap. Recalling this: 2 seconds vs rethinking from scratch: 10-12 seconds.

substitutionEmail Components: Username@MAILSERVER

Visualise the @ symbol as an arrow pointing right: username @→ domain. The domain (right side) is the mail server address. The question will give you options like "@ symbol," "username," "domain name," "subject line" — only the domain name is the server identifier. The @ is just a separator character. Substituting this mental image: instant elimination of 3 wrong options in 2 seconds.

patternSSL vs TLS: Old Name, New Protocol

"SSL is dead, TLS runs the world — but everyone still calls it SSL." Treat any option with SSL/TLS as one unit. If a question asks about secure transactions and offers both "SSL" and "SSL/TLS" as options, "SSL/TLS" is always preferred because it acknowledges both the legacy name and the current standard. If only one appears, pick it over HTTP/FTP/SMTP without hesitation — those three are never used for encryption. Decision time: 3 seconds vs 15 seconds of second-guessing.


Fast-Solving Framework

When you see an Internet Basics question in the exam, run this decision tree:

Step 1 — Identify the question type:

Step 2 — Eliminate first, confirm second. Most internet basics questions have two clearly wrong options. Remove them in 2 seconds, then choose between the remaining two using the specific rule.

Step 3 — If genuinely unsure between two: pick the more specific option. "SSL/TLS" beats "HTTPS" for encryption-mechanism questions. "Domain name" beats "@ symbol" for server-identifier questions.

Target time per question: 20-25 seconds.


Solved PYQs

Why this question: Tests whether you know the internal structure of an email address — a commonly misunderstood concept where students confuse the role of @ with the domain name.

Previous Year Questionपिछले वर्ष का प्रश्न
Which component of an email address identifies the mail server?
ईमेल एड्रेस में मेल सर्वर की पहचान कौन सा हिस्सा करता है?
  1. Username
  2. @ symbol
  3. Domain name
  4. Subject line
  1. यूज़रनेम
  2. @ सिंबल
  3. डोमेन नेम
  4. सब्जेक्ट लाइन
Solutionसमाधान
In an email address like user@example.com, the domain name (example.com) identifies the mail server that handles the email account. The part before @ is the username.
user@example.com जैसे ईमेल पते में, डोमेन नाम (example.com) उस मेल सर्वर की पहचान करता है जो ईमेल खाते को संभालता है। @ से पहले का हिस्सा उपयोगकर्ता नाम है।

Solving path: Reconstruct a real address — user@example.com. The @ is a separator, not a server identifier. "Domain name" = example.com = the mail server. Eliminate username (identifies the mailbox, not server), @ symbol (separator), subject line (part of email content, not address). Answer: Domain name. Time: 10 seconds.


Why this question: Protocol-to-function mapping is the most frequently tested concept. Students confuse FTP with HTTP because both are "transfer" protocols — but HTTP transfers web page data, FTP transfers files explicitly.

Previous Year Questionपिछले वर्ष का प्रश्न
Which protocol is used for transferring files over the internet?
इंटरनेट पर फ़ाइलें ट्रांसफर करने के लिए कौन सा प्रोटोकॉल इस्तेमाल किया जाता है?
  1. HTTP
  2. SMTP
  3. FTP
  4. POP3
  1. HTTP
  2. SMTP
  3. FTP
  4. POP3
Solutionसमाधान
FTP (File Transfer Protocol) is specifically designed for transferring files between computers over a network. It supports both uploading and downloading files to/from remote servers.
FTP (फाइल ट्रांसफर प्रोटोकॉल) विशेष रूप से नेटवर्क पर कंप्यूटरों के बीच फाइलों को स्थानांतरित करने के लिए डिज़ाइन किया गया है। यह रिमोट सर्वर से फाइलों को अपलोड और डाउनलोड करने का समर्थन करता है।

Solving path: Apply SAFE — F = FTP = File transfer. Eliminate HTTP (web pages), SMTP (sending mail), POP3 (receiving mail). Answer: FTP. Time: 8 seconds.


Why this question: Abbreviation questions at SBI PO are designed to catch candidates who know the term but not the exact full form — "Internet Security Protocol" sounds plausible.

Previous Year Questionपिछले वर्ष का प्रश्न
What does ISP stand for in internet terminology?
इंटरनेट की भाषा में ISP का पूरा नाम क्या है?
  1. Internet Security Protocol
  2. Internet Service Provider
  3. Internal System Process
  4. Internet Software Package
  1. Internet Security Protocol
  2. Internet Service Provider
  3. Internal System Process
  4. Internet Software Package
Solutionसमाधान
ISP stands for Internet Service Provider. These are companies that provide internet access to consumers and businesses, such as Airtel, Jio, BSNL in India.
ISP का मतलब Internet Service Provider है। ये ऐसी कंपनियां हैं जो उपभोक्ताओं और व्यवसायों को इंटरनेट एक्सेस प्रदान करती हैं, जैसे भारत में एयरटेल, जियो, BSNL।

Solving path: ISP = Internet Service Provider. The giveaway is that options B and C use "Service" vs "System" — ISP is a company (provider), not a system or process. Examples like Airtel/Jio confirm "Service Provider." Answer: Internet Service Provider. Time: 8 seconds.


Why this question: The HTTP vs HTTPS distinction is directly relevant to banking security — SBI PO exam treats this as a financial literacy question disguised as computer knowledge.

Previous Year Questionपिछले वर्ष का प्रश्न
Which protocol is primarily used for secure data transmission over the internet?
इंटरनेट पर सुरक्षित डेटा ट्रांसमिशन के लिए मुख्य रूप से कौन सा प्रोटोकॉल इस्तेमाल होता है?
  1. HTTP
  2. HTTPS
  3. FTP
  4. SMTP
  1. HTTP
  2. HTTPS
  3. FTP
  4. SMTP
Solutionसमाधान
HTTPS (HyperText Transfer Protocol Secure) is the secure version of HTTP that uses SSL/TLS encryption to protect data during transmission between a web browser and server.
HTTPS (हाइपरटेक्स्ट ट्रांसफर प्रोटोकॉल सिक्योर) HTTP का सुरक्षित संस्करण है जो वेब ब्राउज़र और सर्वर के बीच डेटा ट्रांसमिशन के दौरान SSL/TLS एन्क्रिप्शन का उपयोग करके डेटा को सुरक्षित रखता है।

Solving path: "Secure" is the keyword. HTTP is insecure (port 80). HTTPS adds SSL/TLS encryption (port 443). FTP is for files, SMTP for mail — neither handles web security. Answer: HTTPS. Time: 6 seconds.


Why this question: Tests the specific mechanism behind secure transactions — a level deeper than just knowing HTTPS exists. Candidates who only memorised "HTTPS = secure" without knowing SSL/TLS underlies it will get this wrong.

Previous Year Questionपिछले वर्ष का प्रश्न
Which technology enables secure online transactions through encryption?
कौन सी टेक्नोलॉजी एन्क्रिप्शन के जरिए ऑनलाइन ट्रांजैक्शन को सुरक्षित बनाती है?
  1. HTTP
  2. SSL/TLS
  3. FTP
  4. SMTP
  1. HTTP
  2. SSL/TLS
  3. FTP
  4. SMTP
Solutionसमाधान
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) provide encryption and authentication for secure online transactions, protecting sensitive data like credit card information during transmission.
SSL (सिक्योर सॉकेट्स लेयर) और इसका उत्तराधिकारी TLS (ट्रांसपोर्ट लेयर सिक्योरिटी) सुरक्षित ऑनलाइन लेनदेन के लिए एन्क्रिप्शन और प्रमाणीकरण प्रदान करते हैं, ट्रांसमिशन के दौरान क्रेडिट कार्ड जानकारी जैसे संवेदनशील डेटा की सुरक्षा करते हैं।

Solving path: The question asks about the encryption technology, not the protocol label. HTTP = plaintext. FTP = file transfer. SMTP = email. SSL/TLS = the actual encryption engine inside HTTPS. Answer: SSL/TLS. Time: 10 seconds.


Why this question: URL full form is a perennial favourite with a deliberate trap — "Universal" vs "Uniform."

Previous Year Questionपिछले वर्ष का प्रश्न
What does 'URL' stand for?
'URL' का पूरा नाम क्या है?
  1. Universal Resource Locator
  2. Uniform Resource Locator
  3. Universal Reference Link
  4. Uniform Reference Locator
  1. Universal Resource Locator
  2. Uniform Resource Locator
  3. Universal Reference Link
  4. Uniform Reference Locator
Solutionसमाधान
URL stands for Uniform Resource Locator. It is the address used to access resources on the internet, typically consisting of protocol, domain name, and path components.
URL का मतलब Uniform Resource Locator है। यह इंटरनेट पर संसाधनों तक पहुंचने के लिए उपयोग किया जाने वाला पता है, जो आमतौर पर प्रोटोकॉल, डोमेन नाम और पथ घटकों से मिलकर बना होता है।

Solving path: URLs follow a fixed, standardised format — Uniform. "Universal" would mean usable by all types of devices (that is USB's domain). Eliminate options A, C, D. Answer: Uniform Resource Locator. Time: 6 seconds.


Why this question: Port numbers are tested directly at SBI PO level, particularly the distinction between HTTP (80) and HTTPS (443) — confusing these is the intended trap.

Previous Year Questionपिछले वर्ष का प्रश्न
Which port number is commonly used for secure web traffic (HTTPS)?
सिक्योर वेब ट्रैफ़िक (HTTPS) के लिए आमतौर पर कौन सा पोर्ट नंबर इस्तेमाल किया जाता है?
  1. 80
  2. 443
  3. 21
  4. 25
  1. 80
  2. 443
  3. 21
  4. 25
Solutionसमाधान
Port 443 is the standard port for HTTPS (secure web traffic). Port 80 is used for HTTP, port 21 for FTP, and port 25 for SMTP email.
पोर्ट 443 HTTPS (सुरक्षित वेब ट्रैफ़िक) के लिए मानक पोर्ट है। पोर्ट 80 HTTP के लिए, पोर्ट 21 FTP के लिए, और पोर्ट 25 SMTP ईमेल के लिए उपयोग किया जाता है।

Solving path: Recall the grid — HTTPS = port 443. Port 80 = HTTP (insecure), port 21 = FTP, port 25 = SMTP. The question specifies "secure web traffic," confirming 443. Answer: 443. Time: 5 seconds.


Why this question: Cookies are frequently mischaracterised in trick options — "store passwords" and "block ads" are deliberate distractors targeting students who have heard of cookies without knowing their precise function.

Previous Year Questionपिछले वर्ष का प्रश्न
What is the purpose of cookies in web browsing?
वेब ब्राउज़िंग में cookies का क्या काम होता है?
  1. To store website passwords
  2. To increase internet speed
  3. To store user preferences and session information
  4. To block unwanted advertisements
  1. वेबसाइट के पासवर्ड स्टोर करना
  2. इंटरनेट की स्पीड बढ़ाना
  3. यूज़र की प्राथमिकताएं और सेशन की जानकारी स्टोर करना
  4. अनचाहे विज्ञापनों को ब्लॉक करना
Solutionसमाधान
Cookies are small text files stored by websites on a user's device to remember user preferences, login status, shopping cart contents, and other session-related information for enhanced user experience.
कुकीज़ वेबसाइटों द्वारा उपयोगकर्ता के डिवाइस पर संग्रहीत छोटी टेक्स्ट फाइलें हैं जो उपयोगकर्ता की प्राथमिकताओं, लॉगिन स्थिति, शॉपिंग कार्ट सामग्री और बेहतर उपयोगकर्ता अनुभव के लिए अन्य सत्र-संबंधित जानकारी को याद रखती हैं।

Solving path: Cookies store session state — login status, preferences, cart contents. They do not store passwords (password managers do that separately), increase speed (that is caching), or block ads (ad blockers do that). Answer: To store user preferences and session information. Time: 10 seconds.


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