13.2 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 primary (master) name server maintains its zone data in several database files, and can transfer this information periodically to any backup (slave) name servers that are also configured in the zone. 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 primary name server, a backup (slave) name server maintains a copy of the zone data, which it periodically refreshes from the primary server's copy.

Stub name server

A primary name server for a zone might also be configured as a stub name server that maintains information about the primary and backup 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.