Authoritative nameserver
An authoritative nameserver is the server that holds the actual source-of-truth records for a DNS zone and is designated, via NS records at both the registrar and the zone itself, to answer queries about that domain directly -- as opposed to a recursive resolver, which only caches and forwards answers it looked up elsewhere. When a recursive resolver doesn't have a cached answer, it eventually queries one of the domain's authoritative nameservers to get the current, canonical record. Changing DNS providers means updating which servers are authoritative for a domain at the registrar, and until every resolver's cached copy of the old NS records expires, some queries may still reach the old servers. Confirming which nameservers are actually authoritative for a domain, and that they match what was intentionally configured, is a basic check against DNS hijacking or an unnoticed registrar change.
By AdminKit team, Netbase JSC · Updated