How DNS Actually Works — From URL to IP in 30ms

A print-ready, 2-page A4 interview cheat sheet distilled from my DNS video.

Front — the concept in 60 seconds: the whole lookup chain (browser cache → OS → hosts file → resolver → root → TLD → authoritative) in under 180 words, an everyday analogy that makes it stick, and the delegation-chain diagram. All the memorizable numbers: port 53, TTLs, 13 root addresses, ~30 ms cold walk.

Back — the questions they'll actually ask: the 6 most-asked DNS interview questions with complete, say-this answers (recursive vs authoritative, record types, TTL & propagation, why hierarchical, why UDP/53) plus the 3 traps candidates fall into.

For SDE / backend / infra interview prep. Instant download.