Forwarders

Normally, name servers answer queries from cached data or, if that does not succeed, they attempt to contact other name servers identified in their data files as authoritative for certain domains. However, name servers can also be configured to contact special servers called forwarders before contacting the name servers listed in their data files. If a forwarder cannot process the query and if the local name server is not a forward-only name server, the local name server contacts the name servers in its data files. A forward-only name server relies completely on its forwarders. It does not try to contact other servers to find out information if the forwarders do not give it an answer.

The forwarding function is useful for reducing the number of queries to servers on the Internet and for creating a large cache of information on forwarders. It is also a useful function for providing Internet access for local servers that, for one reason or another, do not have access themselves.