juniorDevOps
How does DNS Resolution work?
Updated Apr 28, 2026
Short answer
DNS translates human-readable domain names (example.com) into IP addresses (192.0.2.1) that computers use to connect.
Deep explanation
The process: 1) Check local browser/OS cache. 2) Query the ISP's Recursive Resolver. 3) Query the Root Nameserver. 4) Query the TLD Nameserver (.com). 5) Query the Authoritative Nameserver (Route53/Cloudflare), which returns the A/AAAA record IP address.
Real-world example
Updating an A Record in AWS Route53 to point api.company.com to a new Elastic IP address of an EC2 instance.
Common mistakes
- Assuming DNS propagation is instant across the globe
- DNS caching depends on the TTL (Time To Live) value.
Follow-up questions
- What is a CNAME record?