EXPERTInfrastructure

Design a Global DNS System

Design a globally distributed DNS system like Cloudflare or Route 53 that handles billions of queries per day.

Estimated Time: 45 minutes
#DNS#GeoDNS#Caching#Anycast
Solution Overview

Use Anycast for geographic routing. Implement hierarchical caching with TTL-based invalidation. Handle DNS amplification attacks.

Hints to Get Started
1

How does DNS resolution work?

2

Caching strategies at each level

3

DDoS protection mechanisms

Dns Hierarchy
  • Root servers
  • TLD servers
  • Authoritative servers
  • Recursive resolvers
Optimizations
  • Anycast routing
  • EDNS Client Subnet
  • DNS over HTTPS/TLS