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DNS Resolution

Query Flow​

  1. Client stub resolver asks recursive resolver.
  2. Resolver queries root -> TLD -> authoritative nameserver.
  3. Response is cached according to TTL.

Common Failure Modes​

  • NXDOMAIN from wrong record name.
  • Stale cache after recent migration.
  • Resolver timeout under traffic spikes.

Useful Commands​

dig api.example.com
dig +trace api.example.com