Skip to content

Artificial Intelligence, Data Analytics and Cyber Security - Laws and Practice · Network Basics and Security

Internet, IP Addressing and Network Protocols Explained

Updated 11 October 2026 · Fact-checked

The internet is a global network of networks that exchange data using common rules called protocols. Every device gets an IP address (IPv4 or IPv6). DNS converts names to IP addresses. HTTP and HTTPS carry web pages, FTP moves files. To solve questions, define, compare, then give an example.

Understand Internet, IP Addressing and Network Protocols

The internet is a worldwide network of connected networks. Your phone, a company server and a bank's system can talk to each other because they all follow the same rules. These rules are called protocols. A protocol fixes how data is formatted, addressed, sent and checked.

Every device on a network needs an address so data reaches the right place. This is the IP address. IPv4 uses 32 bits, written as four numbers from 0 to 255 separated by dots, for example 192.168.1.10. It gives about 4.3 billion addresses, which have run short. IPv6 uses 128 bits, written as eight groups of hexadecimal digits separated by colons, for example 2001:0db8:0000:0000:0000:0000:0000:0001. It gives a vastly larger address space. IPv6 also allows shortened writing: leading zeros can be dropped, and one run of all-zero groups can be replaced by ::.

People remember names, not numbers. The Domain Name System (DNS) works like a phone book. You type a name such as www.example.com. Your device asks a DNS resolver. The resolver, if it does not already have the answer saved (cached), asks the root, top-level domain (.com, .in) and authoritative name servers in turn. It returns the IP address, and your browser connects to it.

HTTP (Hypertext Transfer Protocol) is the rule set for requesting and sending web pages. It sends data as plain text, so anyone who intercepts it can read it. HTTPS is HTTP run over an encryption layer (TLS, earlier called SSL). It encrypts the data, checks the server's identity through a digital certificate and detects tampering. Banking, e-filing and payment sites must use it.

Other protocols do other jobs. FTP transfers files; SFTP does so securely. SMTP sends email, while POP3 and IMAP receive it. DHCP hands out IP addresses automatically. SSH gives secure remote login. Each application protocol has a standard port number, which identifies the service on a device.

Key rules to remember

IPv4 address size
32 bits = 4 octets × 8 bits; each octet 0 to 255; total addresses = 2^32
2^32 is about 4.3 billion. Written in dotted decimal.
IPv6 address size
128 bits = 8 groups × 16 bits; total addresses = 2^128
Written in hexadecimal separated by colons. :: may replace one run of zero groups, only once per address.
Common default ports (1)
HTTP 80 | HTTPS 443 | FTP 21 (control) and 20 (data) | SSH 22 | SFTP 22
SFTP runs over SSH, so it shares port 22.
Common default ports (2)
SMTP 25 | DNS 53 | DHCP 67/68 | POP3 110 | IMAP 143
These are default ports. Services can be configured on other ports.
HTTPS composition
HTTPS = HTTP + TLS/SSL encryption
Gives confidentiality, server authentication and integrity.

How to solve Internet, IP Addressing and Network Protocols questions

Questions on this topic are usually 'explain', 'distinguish' or 'apply to a scenario'. Use one structure for all of them.

  1. 1Read the verb: define, distinguish, explain working, or advise on a scenario.
  2. 2Define the main term in one or two lines with its full form.
  3. 3State the core mechanism or feature, such as bit length, resolution steps or encryption.
  4. 4For a comparison, list 4 to 5 points side by side in the same order for both items: size, format, security, use, port or example.
  5. 5Add the port number or a real example, such as a bank website using HTTPS.
  6. 6For a scenario, name the protocol that fits and give the reason, then mention the risk if a weaker option is used.
  7. 7Close with a one-line conclusion tying to security or compliance.

Quickest way: Define, compare, example

When to use it: Use when time is short and the question asks you to distinguish or explain a protocol.

  1. Write the full form and one-line purpose.
  2. Give 4 comparison points in a short list.
  3. Add the port number and one Indian example.
  4. End with the security implication in one line.

Common mistakes in Internet, IP Addressing and Network Protocols

  • Saying IPv4 has 64 bits or IPv6 has 64 bits.

    Students mix up bit lengths with the number of octets or groups.

    Fix: Remember 32 for IPv4 (4 × 8) and 128 for IPv6 (8 × 16).

  • Claiming DNS gives the website's content.

    The word 'server' makes students think DNS hosts pages.

    Fix: DNS only returns the IP address. The web server then supplies the page over HTTP or HTTPS.

  • Writing that HTTPS makes a website trustworthy or safe from all attacks.

    Students overstate the padlock symbol.

    Fix: Say HTTPS protects data in transit and confirms the server's identity. The site itself can still be malicious or have weak security.

  • Swapping ports, such as FTP 22 or SSH 21.

    Numbers are memorised without association.

    Fix: Learn in pairs: FTP 21, SSH 22, SMTP 25, DNS 53, HTTP 80, HTTPS 443. Practise by writing them from memory.

  • Treating FTP as secure.

    Students assume file transfer in a corporate setting is protected.

    Fix: Plain FTP sends credentials and data unencrypted. Name SFTP or FTPS as the secure alternative.

  • Writing IPv6 as dotted decimal or using :: more than once.

    Students carry IPv4 format over, or shorten freely.

    Fix: IPv6 uses hexadecimal groups with colons. :: can appear only once in an address.

Worked examples

Example 1

Distinguish between IPv4 and IPv6. (Answer in a structured form.)

Show the solution
  1. Define: both are versions of the Internet Protocol that give each device a unique logical address.
  2. Size: IPv4 is 32 bits; IPv6 is 128 bits.
  3. Format: IPv4 is four decimal octets separated by dots, e.g. 192.168.1.10. IPv6 is eight hexadecimal groups separated by colons, e.g. 2001:db8::1.
  4. Address space: IPv4 has 2^32 addresses (about 4.3 billion) and is running short. IPv6 has 2^128 addresses, enough for the growth of devices such as IoT.
  5. Configuration and security: IPv4 often depends on DHCP or manual setup, and IPsec is optional. IPv6 supports auto-configuration, and IPsec support is built into the specification.
  6. Conclusion: IPv6 solves address exhaustion and is designed for large-scale connected devices, but both run side by side during transition.

Answer: IPv4 is a 32-bit dotted-decimal address with about 4.3 billion addresses. IPv6 is a 128-bit hexadecimal colon-separated address with a vastly larger space, auto-configuration and built-in IPsec support.

Example 2

A Mumbai-based company's employee types www.examplebank.in into a browser. Explain how the site is reached and why the bank must use HTTPS rather than HTTP.

Show the solution
  1. The browser checks its cache and the operating system for a stored IP address. If none is found, it asks the DNS resolver.
  2. The resolver queries the root server, then the .in top-level domain server, then the authoritative name server for examplebank.in. The IP address is returned and cached.
  3. The browser connects to that IP address on port 443 for HTTPS (port 80 for HTTP).
  4. With HTTPS, a TLS handshake takes place. The server presents a digital certificate, the browser verifies it, and an encrypted session is set up.
  5. With plain HTTP, login details and account data would travel in readable form and could be intercepted or altered on the network.
  6. HTTPS gives confidentiality, server authentication and integrity, which supports the bank's duty to follow reasonable security practices for sensitive data.

Answer: DNS translates the name to an IP address, then the browser connects on port 443 and sets up a TLS-encrypted session. The bank must use HTTPS because HTTP sends data unencrypted and exposes customers' credentials and financial data.

Exam tips

  • Prepare a ready comparison table-style list for IPv4 vs IPv6 and HTTP vs HTTPS. These are the most likely 'distinguish' questions.
  • Always give port numbers when you name a protocol. It shows precision and costs only a few words.
  • Explain DNS as a sequence of steps, not a definition alone.
  • In scenario questions, link the protocol to a security or legal duty, such as protecting sensitive personal data.
  • Keep the answer within 'provision, analysis, conclusion' form: define, apply to facts, then state the recommendation.

Practice questions from Network Basics and Security

Internet, IP Addressing and Network Protocols: frequently asked questions

What is the main difference between IPv4 and IPv6?

IPv4 uses 32-bit addresses written in dotted decimal. IPv6 uses 128-bit addresses written in hexadecimal with colons. IPv6 was introduced because IPv4 addresses were running out.

How does DNS work in simple words?

DNS turns a website name into an IP address. Your device asks a resolver, which checks its cache or queries root, top-level domain and authoritative servers. The IP address comes back and your browser connects to it.

What is the difference between HTTP and HTTPS?

HTTP sends data in plain text on port 80. HTTPS adds TLS encryption and a server certificate and uses port 443. It protects data in transit and verifies the server.

Which common protocols and ports should I remember?

Remember HTTP 80, HTTPS 443, FTP 21, SSH 22, SMTP 25, DNS 53, POP3 110 and IMAP 143. These are defaults and can be changed by configuration.