Understanding AWS VPC: A Guide to Virtual Private Cloud

It was late at night. Arjun sat with a hot cup of chai, excited to take the first real step into AWS networking.

"Let’s build my first VPC today."

He’d heard of the term — Virtual Private Cloud — but what did it really mean?

🔍 What is a VPC?

A VPC (Virtual Private Cloud) is like your own private data center inside AWS.

Think of it like building your own gated colony inside a massive city — the city being AWS.

✅ Only private IPv4 ranges are allowed — like:
10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16

CIDR stands for Classless Inter-Domain Routing — it's how you define how many IPs you want.

Let’s say Arjun wants to create a VPC with this range:

10.0.0.0/16

That gives him 65,536 IP addresses to play with.

"Plenty of space for my app servers, databases, and future microservices."

But here’s the catch 👇

Arjun’s friend once made this mistake:
He created two VPCs with the same IP range:

VPC A: 10.0.0.0/16  
VPC B: 10.0.0.0/16

Later, when he tried to connect them using VPC peering — 💥 it failed.

🚫 Why? Because IP ranges were overlapping.

So here’s the golden rule:

🧠 Always make sure your VPC's CIDR doesn’t overlap with:

Other VPCs

On-prem corporate network

VPN-connected regions

It’s like giving every colony in a city a unique pin code so that there’s no confusion.

At the end of this session, Arjun will have:

It’s the foundation of his cloud architecture.

So if you’re just starting your AWS networking journey:

Arjun didn’t build his cloud empire in a day.
But starting with a clean, well-designed VPC?

That was the smartest move he made.
And now, so can you.