Please See Below: Use Only Downward Referrals in the DNS
Oracle
Snake Hill Labs
A server in the Domain Name System can use a mechanism called "referral" to indicate that the server is not authoritative for a given zone, and to redirect the query to another, more appropriate server. The mechanism was originally specified such that a referral might be to any location in the DNS. Operational experience indicates dubious value to referrals other than those to zones below the zones for which a server is authoritative. This memo therefore recommends such referrals and discourages other kinds of referrals.