## 🌐 AWS & DevOps Networking – A Complete Beginner-Friendly Explanation
🌐 AWS & DevOps Networking – A Complete Beginner-Friendly Explanation
Networking is one of the most important foundations when learning AWS and DevOps because every application running in the cloud depends on secure and efficient network connectivity.
In simple words:
Networking = How systems communicate (within cloud, between servers, and with the internet)
☁️ AWS Networking – Core Concepts
1️⃣ VPC (Virtual Private Cloud)
A VPC is your private network inside AWS where you can launch resources like EC2, databases, and load balancers.
It works like your own secure isolated data center in the cloud.
2️⃣ Subnets
A subnet divides your VPC network into smaller sections:
Public Subnet – resources that need internet access (web servers)
Private Subnet – internal resources (databases, backend services)
3️⃣ Internet Gateway (IGW)
Allows resources in public subnets to connect to the internet.
4️⃣ NAT Gateway
Allows private subnet instances to access the internet outbound only, but blocks inbound.
5️⃣ Route Table
Controls how traffic flows between subnets and external networks.
6️⃣ Security Groups
Firewall that controls traffic for individual resources (EC2, RDS).
Works at instance level.
7️⃣ NACL (Network Access Control List)
Firewall that protects subnets.
Works at network level.
8️⃣ Load Balancer
Distributes traffic across multiple servers for high availability & performance.
9️⃣ VPC Peering / Transit Gateway
Connects multiple VPCs for large enterprise architecture.
🔧 Networking in DevOps
DevOps networking ensures connectivity and automation between servers, tools, infrastructure, and CI/CD pipelines.
🧰 Key DevOps Networking Areas:
DNS & Domain management (Route53 / Cloudflare)
Reverse proxy & load balancing (NGINX / HAProxy / AWS ALB/NLB)
Kubernetes networking (ClusterIP, NodePort, LoadBalancer, Ingress)
CI/CD pipeline access control
Firewall & VPN management
🔥 Why Networking Matters in DevOps
Reason Explanation
Security Protect infrastructure & data
Connectivity Enables smooth communication
Scalability Support high traffic & autoscaling
Troubleshooting Debug failures & outages
🧠 Real-World Example
A user opens a website → Request goes to Load Balancer → Forwards to EC2 in public subnet → Communicates with Database in private subnet → Response goes back securely to the user.
🚀 Summary
Concept Purpose
VPC Private cloud network
Public / Private Subnet Organize & secure resources
IGW / NAT Internet access control
Route Tables Traffic routing
SG / NACL Firewall security
Load Balancer Distribute traffic
DevOps Networking Reliable deployment connectivity
🤝 Final Note
Mastering AWS & DevOps networking builds a strong foundation for advanced technologies like:
Kubernetes
CI/CD Pipelines
Microservices Architecture
Cloud Security
If you’re learning AWS & DevOps:
👉 Let’s connect & grow together!
AWS #DevOps #Networking #VPC #CloudComputing #DailyLearning #TechCommunity
📘 Basic Networking Concepts
| Q.No | Question | Answer |
|---|---|---|
| 1 | What is computer networking? | Networking means connecting two or more computers to share data, files, or resources. |
| 2 | What are the types of networks? | LAN, MAN, WAN |
| 3 | What is an IP address? | A unique number that identifies a device on a network. |
| 4 | Types of IP Address? | IPv4 and IPv6 |
| 5 | Difference between IPv4 & IPv6? | IPv4 uses 32 bits; IPv6 uses 128 bits (provides more addresses). |
| 6 | What is a private IP address? | Used inside a private network (like home or office LAN). |
| 7 | What is a public IP address? | Used to identify devices over the internet. |
| 8 | What is a MAC address? | A unique hardware identifier assigned to every device. |
| 9 | What is a subnet? | Divides a network into smaller parts for security and performance. |
| 10 | What is a gateway? | Connects one network to another (usually to the internet). |
| 11 | What is DNS? | Domain Name System – converts domain name to IP address. |
| 12 | What is DHCP? | Automatically assigns IP addresses to devices. |
| 13 | What is a router? | Connects multiple networks and forwards data packets. |
| 14 | What is a switch? | Connects devices in the same network and manages communication. |
| 15 | What is a hub? | Basic network device that connects multiple systems without traffic filtering. |
🧠 Network Concepts & Commands
| Q.No | Question | Answer |
|---|---|---|
| 16 | What is TCP/IP? | A set of communication rules used on the internet. |
| 17 | TCP vs UDP? | TCP is reliable & connection-based; UDP is faster & connectionless. |
| 18 | What is Ping? | Used to check network connectivity between two systems. |
| 19 | What is latency? | Delay in data communication time. |
| 20 | What is bandwidth? | Amount of data that can be transferred per second. |
| 21 | What is packet loss? | When some network packets fail to reach destination. |
| 22 | What is the OSI model? | A 7-layer framework describing network communication. |
| 23 | Name OSI Layers | Physical, Data Link, Network, Transport, Session, Presentation, Application |
| 24 | OSI vs TCP/IP model | OSI = 7 layers, TCP/IP = 4 layers. |
| 25 | What is an IP class? | A, B, C, D, E – defines device capacity based on range. |
| 26 | What is a firewall? | Protects network by controlling traffic flow. |
| 27 | What is NAT? | Converts private IP to public IP for internet access. |
| 28 | What is a proxy server? | Intermediate server for security & performance. |
| 29 | What is VPN? | Enables secure remote access via encrypted tunnel. |
| 30 | What is port number? | Identifies a specific service (Example: HTTP uses port 80). |
☁️ Networking in Cloud & AWS
| Q.No | Question | Answer |
|---|---|---|
| 1 | What is a VPC in AWS? | A Virtual Private Cloud is your private network inside AWS where resources run securely. |
| 2 | What is a subnet in AWS? | A smaller network inside a VPC used to organize and isolate resources. |
| 3 | Difference between Public & Private Subnet? | Public subnet has internet access, private subnet does not. |
| 4 | What is an Internet Gateway? | A component that connects the VPC to the internet. |
| 5 | What is a NAT Gateway? | Allows private subnet instances to access the internet securely. |
| 6 | What is a Route Table? | Defines how traffic flows between networks inside the VPC. |
| 7 | What is a Security Group? | A virtual firewall that controls inbound & outbound traffic for resources like EC2. |
| 8 | What is a Network ACL (NACL)? | Firewall applied at the subnet level to control traffic. |
| 9 | What is an Elastic IP? | A static public IP address assigned to AWS resources. |
| 10 | What is a Load Balancer? | Distributes incoming application traffic across multiple servers. |
🧩 Network Commands & Troubleshooting
| Q.No | Question | Answer |
|---|---|---|
| 11 | What does ifconfig / ip addr do? | Displays or configures network interface details. |
| 12 | What is the ping command? | Tests connectivity between two systems. |
| 13 | What is traceroute? | Shows the path packets take to reach a destination. |
| 14 | What does netstat show? | Displays active network connections and listening ports. |
| 15 | What is nslookup used for? | Checks DNS records for a domain. |
| 16 | What is dig command? | Provides detailed DNS lookup information. |
| 17 | What is ARP? | Maps IP addresses to MAC addresses. |
| 18 | How to check open ports in Linux? | Using netstat -tuln or ss -tuln. |
| 19 | How to check default gateway? | Using ip route show or route -n. |
| 20 | What to check if EC2 instance is not reachable? | Check SG, NACL, Route Table, Elastic IP, running state. |
🔌 Additional Network Concepts
| Q.No | Question | Answer |
|---|---|---|
| 21 | Difference between Unicast, Broadcast & Multicast? | Unicast = one-to-one, Broadcast = one-to-all, Multicast = one-to-many. |
| 22 | What is a port number? | Identifies specific network services (e.g., 80-HTTP, 22-SSH). |
| 23 | Why is networking important in AWS & DevOps? | Enables communication between services, applications & cloud infrastructure. |
| 24 | What is IPv4? | Uses 32-bit addressing (e.g., 192.168.1.1). |
| 25 | What is IPv6? | Uses 128-bit addressing (e.g., 2001:db8::1). |
🔥 NETWORKING CLASSES & RANGE
🌐 Networking Basics & IP Addressing
| Q.No | Question | Answer |
|---|---|---|
| 1 | What does “IP” stand for? | Internet Protocol |
| 2 | How many bits are in an IPv4 address? | 32 bits |
| 3 | How many bits are in an IPv6 address? | 128 bits |
| 4 | How many octets are in IPv4? | 4 octets (8 bits each) |
| 5 | Total number of IPv4 addresses? | 4,294,967,296 (2³²) |
| 6 | Default subnet mask for Class A | 255.0.0.0 (/8) |
| 7 | Default subnet mask for Class B | 255.255.0.0 (/16) |
| 8 | Default subnet mask for Class C | 255.255.255.0 (/24) |
| 9 | Most common network class in homes/offices? | Class C |
| 10 | Which class supports the most hosts? | Class A |
🏷 IP Classes & Ranges
| Q.No | Question | Answer |
|---|---|---|
| 11 | How many IP classes exist? | Five — A, B, C, D, E |
| 12 | Class A Range | 1.0.0.0 – 126.255.255.255 |
| 13 | Class B Range | 128.0.0.0 – 191.255.255.255 |
| 14 | Class C Range | 192.0.0.0 – 223.255.255.255 |
| 15 | Class D & E purpose | D = Multicast, E = Research/Experimental |
| 16 | What is a Private IP? | Used inside internal networks |
| 17 | What is a Public IP? | Unique globally, used on the internet |
| 18 | Private IP Range Class A | 10.0.0.0 – 10.255.255.255 |
| 19 | Private IP Range Class B | 172.16.0.0 – 172.31.255.255 |
| 20 | Private IP Range Class C | 192.168.0.0 – 192.168.255.255 |
🔐 Private vs Public IP
| Q.No | Question | Answer |
|---|---|---|
| 21 | Can two networks use same private IPs? | Yes |
| 22 | Can two devices share same public IP? | No |
| 23 | Which IP is used inside AWS VPC? | Private IP |
| 24 | When does AWS EC2 get Public IP? | In public subnet or manually |
| 25 | Default VPC CIDR in AWS | 172.31.0.0/16 |
| 26 | What is NAT for? | Converts private IP to public |
| 27 | What is Elastic IP? | Static public IP in AWS |
| 28 | Why companies use private IPs? | Security + cost saving |
📦 Subnetting Concepts
| Q.No | Question | Answer |
|---|---|---|
| 29 | What is subnet mask? | Separates network & host bits |
| 30 | What does /24 mean? | 24 bits for network, 8 for hosts |
| 31 | Usable IPs in /24 subnet | 254 |
| 32 | Usable IPs in /16 subnet | 65,534 |
| 33 | Usable IPs in /20 subnet | 4,094 |
| 34 | IPs that cannot be assigned | Network & broadcast IP |
| 35 | What is CIDR? | Classless Inter-Domain Routing |
| 36 | Why CIDR introduced? | Prevent IP wastage |
🧩 AWS Subnetting Examples
| Q.No | Question | Answer |
|---|---|---|
| 37 | CIDR 10.0.0.0/16 total IPs | 65,536 |
| 38 | Range for subnet 10.0.1.0/24 | 10.0.1.0 – 10.0.1.255 |
| 39 | How many IPs AWS reserves? | 5 per subnet |
| 40 | Why AWS reserves 5 IPs? | Networking operations |
| 41 | Example public subnet CIDR | 10.0.1.0/24 |
| 42 | Example private subnet CIDR | 10.0.2.0/24 |
| 43 | Can 2 VPCs have same CIDR? | Yes, but no peering |
| 44 | Issue with overlapping CIDR | Routing conflicts |
| 45 | Selecting VPC CIDR | Depends on expected resources |
| 46 | Benefit of subnetting in AWS | Security & efficient control |
🧠 IP Address Classes And Ranges
| Q.No | Question | Answer |
|---|---|---|
| 1 | What is Class A IP range? | 1.0.0.0 – 126.255.255.255 |
| 2 | Default subnet mask of Class A | 255.0.0.0 (/8) |
| 3 | Example Class A IP | 10.0.0.1 |
| 4 | What is Class B IP range? | 128.0.0.0 – 191.255.255.255 |
| 5 | Default subnet mask of Class B | 255.255.0.0 (/16) |
| 6 | Example Class B IP | 172.16.0.1 |
| 7 | What is Class C IP range? | 192.0.0.0 – 223.255.255.255 |
| 8 | Default subnet mask of Class C | 255.255.255.0 (/24) |
| 9 | Example Class C IP | 192.168.1.1 |
| 10 | Use of Class A | Large networks |
| 11 | Use of Class B | Medium networks |
| 12 | Use of Class C | Small networks / LAN |
| 13 | What is Class D used for? | Multicast |
| 14 | Class E usage | Research & experimental |
| 15 | Private IP range (Class A) | 10.0.0.0 – 10.255.255.255 |
| 16 | Private IP range (Class B) | 172.16.0.0 – 172.31.255.255 |
| 17 | Private IP range (Class C) | 192.168.0.0 – 192.168.255.255 |
| 18 | Are private IPs routable on internet? | No |
| 19 | Are public IPs globally unique? | Yes |
| 20 | Example of AWS default VPC CIDR | 172.31.0.0/16 |
🔥 Most Important Protocols & Ports – Q&A Table
| Q.No | Protocol / Service | Port | Usage / Why Important |
|---|---|---|---|
| 21 | SSH | 22 | Remote login to Linux / AWS EC2 |
| 22 | HTTP | 80 | Web traffic |
| 23 | HTTPS | 443 | Secure web traffic |
| 24 | DNS | 53 | Domain resolution (AWS Route53) |
| 25 | DHCP | 67, 68 UDP | Auto assigns IPs |
| 26 | FTP | 21 | File transfer |
| 27 | SMTP | 25 | Sending mail |
| 28 | IMAP / POP3 | 143 / 110 | Receiving mail |
| 29 | RDP | 3389 | Remote desktop (Windows) |
| 30 | MySQL | 3306 | Database (RDS MySQL) |
| 31 | PostgreSQL | 5432 | Database (RDS PGSQL) |
| 32 | Jenkins | 8080 | CI/CD pipelines |
| 33 | Prometheus | 9090 | Monitoring |
| 34 | Grafana | 3000 | Dashboards |
🧩 Subnetting Examples (AWS) – Already Provided Format
| Q.No | Question | Answer |
|---|---|---|
| 37 | CIDR 10.0.0.0/16 total IPs | 65,536 |
| 38 | Range for subnet 10.0.1.0/24 | 10.0.1.0 – 10.0.1.255 |
| 39 | How many IPs AWS reserves? | 5 per subnet |
| 40 | Why AWS reserves 5 IPs? | Networking operations |
| 41 | Example public subnet CIDR | 10.0.1.0/24 |
| 42 | Example private subnet CIDR | 10.0.2.0/24 |
| 43 | Can 2 VPCs have same CIDR? | Yes, but no peering |
| 44 | Issue with overlapping CIDR | Routing conflicts |
| 45 | Selecting VPC CIDR | Depends on expected resources |
| 46 | Benefit of subnetting in AWS | Security & efficient control |
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