anchor.diff:  
   %% With the extracted Qname and Qtype in hand, find the nearest zone
   %% Step 2: Search the available zones for the zone which is the nearest ancestor to QNAME
  +-spec resolve(dns:message(), [dns:rr()], dns:dname(), dns:type(), dns:ip()) -> dns:message().
   resolve(Message, AuthorityRecords, Qname, Qtype, Host) ->
     Zone = erldns_zone_cache:find_zone(Qname, lists:last(AuthorityRecords)), % Zone lookup
     Records = resolve(Message, Qname, Qtype, Zone, Host, _CnameChain = []),
  
positive.code:   case erldns_config:use_root_hints() of
      true ->
        {Authority, Additional} = erldns_records:root_hints(),
        Message#dns_message{aa = true, rc = ?DNS_RCODE_NOERROR, authority = Authority, additional = Additional};
      _ ->
        Message#dns_message{aa = true, rc = ?DNS_RCODE_NOERROR}
    end;
  
negative.code:       case erldns_config:use_root_hints() of
          true ->
            {Authority, Additional} = erldns_records:root_hints(),
            Message#dns_message{authority = Authority, additional = Message#dns_message.additional ++ Additional};
          _ ->
            Message
        end
  