2. Definitions

For the purposes of this document, and only this document, the following definitions apply:

DNS

The Domain Name System [RFC1034, RFC1035].

Zone

A part of the DNS tree, that is treated as a unit.

Forward Zone

A zone containing data mapping names to host addresses, mail exchange targets, etc.

Reverse Zone

A zone containing data used to map addresses to names.

Server

An implementation of the DNS protocols able to provide answers to queries. Answers may be from information known by the server, or information obtained from another server.

Authoritative Server

A server that knows the content of a DNS zone from local knowledge, and thus can answer queries about that zone without needing to query other servers.

Listed Server

An Authoritative Server for which there is an "NS" resource record (RR) in the zone.

Primary Server

An authoritative server for which the zone information is locally configured. Sometimes known as a Master server.

Secondary Server

An authoritative server that obtains information about a zone from a Primary Server via a zone transfer mechanism. Sometimes known as a Slave Server.

Stealth Server

An authoritative server, usually secondary, which is not a Listed Server.

Resolver

A client of the DNS which seeks information contained in a zone using the DNS protocols.