DNS
DNS resolves domain names to IP addresses, split into recursive and authoritative resolution, forming the foundation of Internet addressing.
Purpose
Understand domain resolution mechanics, configure DNS routing and failover.
Mechanism
Recursive resolvers query from root→TLD→authoritative servers level by level. Record types: A (IPv4), AAAA (IPv6), CNAME (alias), MX (mail), TXT (text). TTL controls cache duration. Route53/Cloudflare support DNS routing policies.
Use cases
- Domain resolution
- Traffic routing
- Failover