Translate Network Scope and Subnets Without False Equivalence
Public and private subnets mean different things on AWS, Azure, and Google Cloud, and interviewers probe for false equivalence. This interactive lesson compares route-table publicness, global versus Regional VPC scope, and private endpoint DNS. Covers: 0.0.0.0/0 routes to an internet gateway, NAT gateways, global Google Cloud VPCs with regional subnets, Azure retired default outbound access, blast-radius reasoning. Prerequisites: VPC and subnet fundamentals.
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In an intermediate cloud networking interview, saying that a public subnet is where public IP addresses live invites a necessary pushback. We are scored on precise scope language and on resisting false equivalence between similarly named constructs. For the seasonal storefront, the relevant distinctions are AWS subnet publicness through routing, Google Cloud Virtual Private Cloud (VPC) scope across Regions, and Azure private-connectivity designs that often depend on Domain Name System (DNS) integration as well as network paths.
Let’s keep one design intent constant. The storefront has public ingress and private application and data tiers across two Availability Zones or zones. The interview task is not to find a universal translation for VPC, VNet, and VPC. Instead, explain which boundary controls ...