Networking Basics For DevOps


π How Does the Internet Work?
π± You use a device (phone, laptop) to open a website or app
Example: You typewww.google.com
π‘ Your device sends a request through Wi-Fi or mobile data
π The request travels through networks (routers, internet cables)
π₯οΈ It reaches a server where the website or app lives
Example: Googleβs server finds your search resultπ¦ The server sends data back (like a reply letter)
π₯οΈ You see the result on your screen
Example: Google shows your search results!
π 3 Tiers of the Internet
ποΈ Tier 1 β The Internet Builders
They own the global internet backbone (undersea + land cables) and connect networks without paying anyone.
πΉ E.g., Tata Comm, AT&T, Lumen
π‘ Theyβre the highways of the internet.
π Tier 2 β The Distributors
They rent access from Tier 1 to distribute internet across cities and countries, connecting ISPs.
πΉ E.g., BSNL, Airtel, Jio core
π‘ Theyβre trucks using highways to deliver between cities.
π Tier 3 β The Last-Mile Providers
They buy bandwidth from Tier 2 and deliver it to homes/offices via local infrastructure.
πΉ E.g., JioFiber, Airtel Xstream, ACT
π‘ Theyβre the delivery guys bringing internet to your door.
πΈοΈ Types of Networks
LAN (Local Area Network) π
A small network in a home or office.
πΉ Example: Your laptop and smart TV connected to the same Wi-Fi.MAN (Metropolitan Area Network) ποΈ
A network across a city or large campus.
πΉ Example: College Wi-Fi that covers all buildings.WAN (Wide Area Network) π
Big network that connects the world.
πΉ Example: The internet β connects servers in the US to users in India.
π OSI Model β 7 Layers
Think of it like sending a parcel π¦ β each layer plays a part!
1οΈβ£ Application β π¬ "What You Use"
Apps like WhatsApp, Gmail, Chrome
π‘ You type a message
2οΈβ£ Presentation β π§ "Formatter"
Encrypts, compresses, translates data
π‘ Turns emojis/text into computer language
3οΈβ£ Session β π "Call Handler"
Starts/stops conversations between devices
π‘ Keeps your Zoom/Gmail session active
4οΈβ£ Transport β π "Safe Delivery"
Breaks data into packets, ensures complete delivery
π‘ Like packing items in boxes
5οΈβ£ Network β πΊοΈ "Router GPS"
Finds the best route for data
π‘ Parcel takes fastest route via IP
6οΈβ£ Data Link β π§© "Local Delivery"
Moves data between nearby devices using MAC
π‘ Delivers to the right flat in a building
7οΈβ£ Physical β β‘ "Cables & Signals"
Sends actual bits via wires or Wi-Fi
π‘ The truck or signal carrying your data
TCP/IP model
real-life systems use a simpler one: TCP/IP model β just 4 layers:
π¨βπ» Application
π Transport
πΊ Network
βοΈ Link
These models helped me understand how data travels β from clicking "send" to reaching someone's browser!
π‘ Protocol
A protocol is like a set of rules π that computers follow to talk to each other smoothly.
π¬ Just like how we follow grammar rules to speak a language, computers follow protocols to send/receive data!
π¨βπ» Must-Know Protocols for DevOps
π 1. HTTP / HTTPS β π
Used for accessing websites
β
Example: Opening Google in a browser
π HTTPS = secure version (data is encrypted)
π‘οΈ 2. SSH (Secure Shell) β ποΈ
Used to securely log in to remote servers
β
Example: Connecting to a Linux server from your laptop
π¬ Like a secret tunnel to your server
π¦ 3. FTP β π
Used to transfer files between systems
β
Example: Uploading files to a web server
π SFTP is the secure version π
π¨ 4. SMTP β π¬
Used for sending & receiving emails
β
Example: Gmail or Outlook behind the scenes
π‘ DevOps may configure these in mail servers
π‘ 5. DNS (Domain Name System) β π§
Translates website names into IP addresses
β
Example: "google.com" β 142.250.67.14
π¬ Like a phonebook for the internet
π Port
A port is like a door πͺ on a computer/server that allows specific types of data in or out.
π‘ Each service (like websites, emails, etc.) uses a specific port number to communicate.
π HTTP (Port 80) β Open websites
β
Example: Accessing http://example.com
π HTTPS (Port 443) β Secure websites
β
Example: Accessing https://google.com
π οΈ SSH (Port 22) β Secure login to servers
β
Example: ssh user@192.168.1.1
(connect to a server remotely)
π FTP (Port 21) β File transfer β Example: Uploading files to a web host
π¬ SMTP (Port 25) β Send emails
β
Example: Used by mail servers to send outgoing emails
π§ DNS (Port 53) β Website name resolution
β
Example: Translating openai.com
to an IP address
π IP and MAC Address?
π IP Address β Your Deviceβs Internet Address
π’ A unique number that identifies your device on the internet.
π Used to send/receive data online
β
Example: 192.168.1.5
π‘ Like your home address π on the internet
π» MAC Address β Your Deviceβs Hardware ID
π‘ A unique code built into your deviceβs network card.
π Used within local networks like Wi-Fi
β
Example: 00:1A:2B:3C:4D:5E
π‘ Like your deviceβs fingerprint π§€ β it never changes
π¦ Subnetting β Network Divider
πΉ Breaks a large network into smaller parts (called subnets)
πΉ Helps organize, secure, and manage IP addresses better
πΉ Saves IPs and improves performance
β Example: A company splits its network into subnets for HR, Sales, and IT
π‘ Like dividing a big apartment into smaller flats π’β‘οΈπ
π DNS (Domain Name System) β Internet Phonebook
πΉ Converts website names into IP addresses
πΉ Makes browsing easy β no need to remember numbers
β
Example: google.com
β‘οΈ 142.250.195.174
π‘ Like finding someoneβs number in a phonebook βοΈ
π₯ DHCP (Dynamic Host Configuration Protocol) β IP Giver
πΉ Automatically gives IP addresses to devices in a network
πΉ No need to assign IPs manually
β Example: When your phone joins Wi-Fi, it gets an IP from the router
π‘ Like a receptionist π§βπΌ giving you a room number in a hotel
π‘ Router & πSwitches
π‘ Router β The Internet Connector
π Connects different networks (like your home to the internet)
π Sends data between your devices and the internet
β
Example: Your Wi-Fi router at home
π‘ Like a traffic cop π¦ directing internet to the right place
π Switch β The Device Connector
π Connects devices inside the same network (like PCs, printers)
π Sends data within your home or office
β
Example: Office switch connecting multiple computers
π‘ Like a power strip π for internet β connecting many devices locally
π VPC (Virtual Private Cloud)
πΉ Your own private network inside AWS
πΉ You control IPs, subnets, gateways, etc.
β Like your own private office space in the cloud π’
βοΈ Load Balancer
πΉ Distributes traffic to multiple servers
πΉ Helps with high availability and better performance
β Like a traffic cop π¦ sending cars (users) to the least busy road (server)
π₯ Firewall
πΉ Blocks or allows network traffic based on rules
πΉ Protects your network from unwanted access
β Like a security gate π§ checking who can enter
π‘οΈ Security Groups
πΉ Virtual firewalls for EC2 instances
πΉ Control which ports (SSH, HTTP, etc.) are open
πΉ Allow inbound/outbound traffic
β Like door rules πͺ: who can come in, and who can go out
π Steps to create EC2 Instance
1οΈβ£ Login to AWS
π Go to aws.amazon.com and sign in to your AWS account.
2οΈβ£ Go to EC2 Dashboard
π₯οΈ Search βEC2β in the AWS console and open the EC2 service.
3οΈβ£ Launch Instance
π Click βLaunch Instanceβ
4οΈβ£ Choose AMI (Amazon Machine Image)
π§ Select an OS like Amazon Linux, Ubuntu, etc.
5οΈβ£ Choose Instance Type
π¦ Pick t2.micro (free tier) if you're testing.
6οΈβ£ Configure Key Pair
π Create/download a key pair to access your instance later (used for SSH login).
7οΈβ£ Set Up Security Group
π‘οΈ Add rules to allow access:
β SSH (port 22) β for login
β HTTP (port 80) β for websites
β HTTPS (port 443) β for secure sites
8οΈβ£ Launch Instance
β
Click βLaunchβ and wait for the instance to run!
9οΈβ£ Connect to Your Instance
π Use SSH with your key file:
Subscribe to my newsletter
Read articles from SARVESH VILAS CHAUDHARI directly inside your inbox. Subscribe to the newsletter, and don't miss out.
Written by
