AWS VPC Architecture Guide: Subnets, Route Tables, NAT Gateways & Transit Gateway

Designing a secure enterprise Amazon VPC (Virtual Private Cloud) requires proper CIDR allocation, public/private subnet segmentation, multi-AZ NAT Gateways, and centralized connectivity via AWS Transit Gateway.

Recommended Subnet Breakdown

• Public Subnets (10.0.1.0/24): Ingress ALBs, NAT Gateways, Bastion hosts.
• Private Application Subnets (10.0.10.0/24): EC2, ECS tasks, Lambda VPC ENIs.
• Database Isolated Subnets (10.0.20.0/24): RDS Aurora endpoints with zero internet access routes.