DNS Lookup

Layer 01 Browser / OS Cache Checks for a fresh answer locally first. Layer 02 Recursive Resolver Performs the lookup on the client’s behalf. Layer 03 Root Nameserver Directs the resolver to the right TLD. Layer 04 TLD Nameserver Points to the domain’s authoritative servers. Layer 05 Authoritative NS Holds the official zone data. Layer 06 Answer Record Returns the final value the app needs.