How DNS Works Inside an AWS VPC

In AWS networking, resources resolve endpoints, services communicate, and applications run as expected. Within a VPC, DNS plays an important role in how services discover each other and how traffic is route. Looking at how DNS actually works inside AWS helps explain why traffic flows the way it does and why certain connections succeed or fail. This article walks through DNS inside an AWS VPC from a networking perspective, focusing on resolution flow rather than application logic. DNS as a Core VPC Service Every VPC comes with a built-in DNS resolver provided by AWS. This resolver is available at a reserved IP address within the VPC and is automatically used by resources unless configured otherwise. When an EC2 instance makes a DNS query, the request does not go directly to the internet. Instead, it is handled internally by the VPC DNS resolver, which decides how and where the name should be resolved. This design allows AWS to integrate DNS tightly with networking, compute, and managed