Software Design

DNS Resolution: Iterative vs Recursive Queries

UML Sequence Diagrams · made in Skemio

UML sequence diagram showing a recursive DNS request from client to resolver, followed by iterative queries to Root, TLD, and Authoritative servers.
UML sequence diagram showing a recursive DNS request from client to resolver, followed by iterative queries to Root, TLD, and Authoritative servers.
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What it shows

  • Recursive resolvers do the heavy lifting on behalf of client devices.
  • Root and TLD servers respond with referrals rather than exact answers.
  • Authoritative servers hold the final source of truth for DNS A records.

The takeaway

Recursive queries offload lookup effort to the resolver, while iterative steps query the DNS hierarchy top-down.

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