Introduction

Computer networking forms the foundation of communication between devices across the globe. Whether it’s sending a simple email or hosting a large website, understanding the principles of networking is essential.
This masterclass article covers everything you need: from basic concepts like LAN, MAN, WAN to advanced topics like OSI layers, TCP/IP protocols, VPCs, and Routing.

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1. Wired Networking

Wired networking refers to connecting devices using physical cables (like Ethernet cables).
It provides reliable, fast, and secure connections, often used in businesses and data centers.

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2. LAN, MAN, WAN Explained

• LAN (Local Area Network):
  Connects devices within a limited area like an office, home, or school (e.g., Wi-Fi network in your house).

• MAN (Metropolitan Area Network):
  Covers a city or a large campus. (e.g., city-wide Wi-Fi).

• WAN (Wide Area Network):
  Spans across countries or continents (e.g., the Internet).

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3. OSI Model: 7 Layers Explained

The OSI Model (Open Systems Interconnection) standardizes networking functions into seven distinct layers.

The 7 Layers:

In simple terms:

• Layers 1-4 handle data delivery.

• Layers 5-7 handle application-level interactions.

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4. TCP/IP Protocol Suite

The TCP/IP model simplifies OSI’s complexity into 4 layers:

Rules Example:

• TCP: Reliable communication, like sending an email.

• IP: Defines addressing so the email knows the path to travel.

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5. Difference Between OSI and TCP/IP Model

Summary:
TCP/IP is what actually powers the Internet. OSI provides a guide to understand networking concepts.

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6. TCP and UDP

• TCP (Transmission Control Protocol):

  • Connection-oriented

  • Reliable and error-checked

  • Example: File download, email transfer

• UDP (User Datagram Protocol):

  • Connectionless

  • Faster but less reliable

  • Example: Streaming videos, online games

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7. IP and MAC Addresses

• IP Address (Internet Protocol):
  Logical address assigned to devices for routing.

• MAC Address (Media Access Control):
  Unique hardware address of a device’s network card.

Think of IP as your home address, and MAC as your fingerprint.

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8. ARP (Address Resolution Protocol)

ARP translates IP addresses to MAC addresses within a LAN.
When a device knows another's IP but needs its MAC to send data, it sends an ARP request.

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9. DNS (Domain Name System)

DNS translates domain names (like google.com) into IP addresses (like 142.250.190.14).
Without DNS, we would have to memorize complex IP addresses instead of simple website names.

How DNS Works:

1. You type www.example.com in your browser.

2. Your computer asks a DNS server to find the matching IP address.

3. The DNS server responds with the correct IP.

4. Your browser connects to the server using the IP address.

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10. DNS Server

A DNS server is a computer that stores a database of domain names and their corresponding IP addresses.

• Types of DNS servers:

  • Recursive Resolver: Finds the data on behalf of the client.

  • Root Name Servers: Direct queries to correct top-level domain servers (.com, .org).

  • Authoritative Name Server: Holds the actual records.

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11. DHCP (Dynamic Host Configuration Protocol)

DHCP automatically assigns IP addresses, subnet masks, gateways, and other networking parameters to devices.

Why it’s important:
Imagine manually assigning IP addresses to thousands of devices — DHCP automates this work.

Example:
When you connect your phone to Wi-Fi, DHCP assigns it an IP address without your involvement.

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12. SSH (Secure Shell)

SSH provides a secure way to remotely log into another computer over an unsecured network.

Uses:

• Remote server access

• Secure file transfers

• Managing network devices

Example:
Developers use SSH to log into cloud servers securely.

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13. SCP (Secure Copy Protocol)

SCP uses SSH for securely transferring files between computers.

Syntax Example:

bashCopyEditscp filename.txt user@remote:/path/

It ensures data is encrypted during transit.

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14. cURL (Client URL)

curl is a command-line tool used to transfer data to or from a server, supporting protocols like HTTP, FTP, and more.

Common use:
Testing APIs or downloading files from a server.

Example:

bashCopyEditcurl https://example.com

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15. VPC (Virtual Private Cloud)

A VPC is a private network inside a public cloud provider (like AWS).

• You control IP address ranges, subnets, route tables, and gateways.

• It's like having your own private data center on the cloud.

Example:
In AWS, you can create a VPC to launch EC2 instances privately.

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16. Subnets

A Subnet (short for subnetwork) divides a larger network (like a VPC) into smaller parts.

• Helps organize networks efficiently.

• Improves security and performance.

Example:
Creating a public subnet for web servers and a private subnet for databases.

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17. Routing

Routing is the process of selecting a path for traffic in a network.

• Router: A device that forwards data packets between networks.

• Route Table: Defines where traffic from your subnet or network should go.

Example:
Sending traffic from a VPC public subnet to the Internet via an Internet Gateway.

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Conclusion

Computer networking is vast but absolutely critical to understand in today's connected world.
From physical wired setups to cloud VPCs, the fundamentals like the OSI model, TCP/IP, and networking protocols (like DNS, DHCP, SSH) form the heart of every online interaction.
If you're aiming to master Cloud Computing, Cybersecurity, DevOps, or any tech field, a strong networking foundation is a must.

Start small, practice consistently, and you’ll soon have networking superpowers!