Authority

When you do a look-up with DNS tools such as dig you may notice the results include information about authority. A DNS Server is considered to be Authoritative if it has local zone files containing the DNS records for the request. It is considered Non-Authoritative if it does not have the zone file for the requested zone. Regardless of whether or not the requested information is in it's DNS cache, if the server does not have the zone file then the reply is non-authoritative.