AWS VPC Networking: Subnets, NAT Gateways, Transit Gateway, and PrivateLink AWS networking is the foundation that everything else sits on, yet it is the area where most teams accumulate the most technical debt. A poorly designed VPC leads to security gaps, connectivity issues, and painful migrations later. Getting your network architecture right from the start - proper CIDR planning, subnet tiers, and connectivity patterns - saves enormous headaches as you scale. Every production VPC should have three subnet tiers across multiple availability zones: public subnets for load balancers and bastion hosts, private subnets for application workloads, and isolated subnets for databases with no internet access. NAT Gateways provide outbound internet access for private subnets - deploy one per AZ for high availability, but be aware they are one of the most expensive networking components.…