AWS VPC Networking Explained

What is a VPC?

A Virtual Private Cloud (VPC) is your own isolated network within AWS. You control IP ranges, subnets, routing, and security — like having a private data center in the cloud.

Core Components

Component	Purpose
Subnet	Subdivision of the VPC
Route Table	Directs traffic
Internet Gateway	Connects to internet
Security Group	Instance firewall
NACL	Subnet firewall

Public vs Private Subnets

• Public subnet — has internet access (web servers).
• Private subnet — no direct internet (databases).

Typical Architecture

VPC (10.0.0.0/16)
 ├─ Public Subnet  (10.0.1.0/24) → Web servers
 └─ Private Subnet (10.0.2.0/24) → Database

Security Layers

Security Groups protect instances; Network ACLs protect subnets — defense in depth.

FAQs

Security Group vs NACL?

Security Groups are stateful (instance level); NACLs are stateless (subnet level). More in our AWS guides.

Why use private subnets?

To keep databases and sensitive resources off the public internet.