APCS Principles Practice Test

When a name can’t be resolved by the local resolver, the lookup climbs the DNS hierarchy. The next step is to query higher-level DNS servers—the root servers first, which direct you to the appropriate top‑level domain (TLD) server, and from there to the domain’s authoritative server. That authoritative server can provide the actual IP address or indicate the domain doesn’t exist. This referral process keeps the lookup moving up the chain until an answer is found or it’s determined there’s no such name.