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Introduction to AWS VPC

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Mahesh Shukla - Aka JailBreaker 🚀 edited this page Mar 18, 2025 · 3 revisions

🔥 AWS VPC Theory Ka Structure (Jo Fast Value De)

1️⃣ Introduction to AWS VPC (CIDR, Private/Public Subnets, Route Tables)
2️⃣ Security Concepts (Security Groups, NACLs, Flow Logs, Bastion Host)
3️⃣ Networking Features (VPC Peering, Transit Gateway, VPN, PrivateLink)
4️⃣ High Availability & Disaster Recovery in VPC
5️⃣ Common VPC Misconfigurations & How to Fix Them

✅ Example: Har topic ke saath practical implementation bhi de, taaki GitHub repo ek knowledge hub bane.
✅ Diagrams & Flowcharts: Agar tu visual diagrams bana sake (draw.io ya Excalidraw se), toh repo aur bhi standout karega.

Tera repo hiring managers aur recruiters ke saamne proof banega ki tu AWS VPC me expert hai.
Kya tu LinkedIn pe bhi AWS VPC ke upar ek pinned post banayega taaki log tujhe notice kare? 🚀

🏗️ Introduction to AWS VPC

🚀 What is AWS VPC?

AWS Virtual Private Cloud (VPC) is a logically isolated network within AWS where you can launch and manage resources securely. It allows complete control over networking, IP addressing, routing, and security.

🔹 Key Concepts of VPC

1️⃣ CIDR (Classless Inter-Domain Routing)

  • CIDR defines the IP address range for your VPC.

  • Example: 10.0.0.0/16 provides 65,536 IPs (10.0.0.0 - 10.0.255.255).

  • Subnetting: The VPC CIDR can be further divided into subnets.

  • Best Practice: Choose a CIDR block that does not overlap with your corporate network.

2️⃣ Subnets (Public & Private)

  • Public Subnet: Has direct internet access via an Internet Gateway (IGW).

  • Private Subnet: No direct internet access. Used for databases and backend servers.

  • Example:

    • 10.0.1.0/24 → Public Subnet

    • 10.0.2.0/24 → Private Subnet

Subnet Best Practices:

✅ Place web servers in public subnets and databases in private subnets. ✅ Use different Availability Zones (AZs) for high availability. ✅ Use NAT Gateway for private subnets to access the internet securely.

3️⃣ Route Tables

  • Route tables control how traffic is directed within the VPC.

  • Main Route Table: Default for all subnets unless explicitly changed.

  • Custom Route Tables: Can be assigned to specific subnets.

  • Example Route Table:

    Destination Target Notes
    10.0.0.0/16 local Allow internal VPC traffic
    0.0.0.0/0 igw-123abc Public subnet internet access
    0.0.0.0/0 nat-xyz123 Private subnet internet access

Route Table Best Practices:

✅ Always separate route tables for public and private subnets. ✅ Avoid unnecessary internet access for security. ✅ Use VPC Peering or Transit Gateway for inter-VPC communication.

📌 Example: Creating a VPC with Public & Private Subnets

Step 1: Create a VPC with CIDR 10.0.0.0/16

aws ec2 create-vpc --cidr-block 10.0.0.0/16

Step 2: Create subnets

aws ec2 create-subnet --vpc-id vpc-123abc --cidr-block 10.0.1.0/24 # Public Subnet
aws ec2 create-subnet --vpc-id vpc-123abc --cidr-block 10.0.2.0/24 # Private Subnet

Step 3: Attach an Internet Gateway (IGW) to the VPC

aws ec2 create-internet-gateway
aws ec2 attach-internet-gateway --vpc-id vpc-123abc --internet-gateway-id igw-xyz123

Step 4: Modify Route Tables

aws ec2 create-route --route-table-id rtb-abc123 --destination-cidr-block 0.0.0.0/0 --gateway-id igw-xyz123

📌 Diagram: Public & Private Subnet Architecture 

                  +-------------------------+
                  |       AWS VPC (10.0.0.0/16)   |
                  +-------------------------+
                            |      
   +-------------------+    +-------------------+
   | Public Subnet    |    | Private Subnet   |
   | 10.0.1.0/24      |    | 10.0.2.0/24      |
   +-------------------+    +-------------------+
           |                         |
 +----------------+        +----------------+
 | Internet Gateway |        |    NAT Gateway    |
 +----------------+        +----------------+

🔥 Real-World Use Cases

✅ Hosting a Web Application: Web servers in a public subnet, databases in a private subnet. ✅ Hybrid Cloud: VPN connects an on-premises data center to AWS VPC. ✅ Multi-Tier Architecture: Load balancer in a public subnet, app servers in private subnets.

📌 Conclusion 

AWS VPC is the backbone of networking in AWS. Understanding CIDR, subnets, and route tables ensures secure and optimized networking. Next, we will explore **Security Groups & Network ACLs!** 🚀
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