Huh, why are people getting hung up on this? The distinction is based on who the DNS server will consult to provide a response to a question.
An authoritative server consults its local authoritative zone database. It may or may not be willing to consult someone else for questions not in its database; as someone else posted, most Internet-facing authoritative servers refuse to provide answers for zones not in their local authoritative database. A recursive server is willing to consult other servers to provide an answer. If the answer is not in its local database (or indeed if it has no local authoritative database), then it's willing to query other name servers to chase down the answers. A forwarding server is a special case of recursive server: It's willing to ask another server for the answer, but in the case of forward-only servers, it's only willing to ask a predefined server or servers for the answer and not go chasing it wherever the DNS leads. In the case of a forward-first server, it first tries its predefined server(s) and then becomes willing to chase it wherever the DNS leads. A given server may be any combination of authoritative, recursive and forwarding depending on the zone. Regardsm Dianne.
