12.2 About Types of Name Servers

You can configure several types of name server using BIND, including:

Master name server

Authoritative for one or more domains, a master name server maintains its zone data in several database files, and can transfer this information periodically to any slave name servers that are also configured in the zone. In older documentation, master name servers are known as primary name servers. An organization might maintain two master name servers for a zone: one master outside the firewall to provide restricted information about the zone for publicly accessible hosts and services, and a hidden or stealth master inside the firewall that holds details of internal hosts and services.

Slave name server

Acting as a backup to a master name server, a slave name server maintains a copy of the zone data, which it periodically refreshes from the master's copy. In older documentation, slave name servers are known as secondary name servers.

Stub name server

A master name server for a zone might also be configured as a stub name server that maintains information about the master and slave name servers of child zones.

Caching-only name server

Performs queries on behalf of a client and stores the responses in a cache after returning the results to the client. It is not authoritative for any domains and the information that it records is limited to the results of queries that it has cached.

Forwarding name server

Forwards all queries to another name server and caches the results, which reduces local processing, external access, and network traffic.

In practice, a name server can be a combination of several of these types in complex configurations.