Types of NameServer

                                                        There are four primary nameserver configuration: 
 

• Master Server: The primary master server is the ultimate source of information about a domain. The primary master is an authoritative server configured to be the source of zone transfer for one or more secondary servers. The primary master server obtains data for the zone from a file on disk.

 

• Slave server: slave server, also called a secondary server is an authoritative server that obtains zone information from Master Server using zone transfer mechanism and act as an alternate to master server for name resolution in the event of master server failure to reply to the query due to failure, overloading or any other reason. 

 

• Cache only server: Some servers are caching only servers. This means that the server caches the information that it receives and uses it until the data expires. A caching only server is a server that is not authoritative for any zone. If the information is not in the cache, this server services queries and asks other servers, who have the authority, for the information it needs.

 

• Forwarding: Forwards request to a specific list of nameservers for name resolution. if none of the specified nameservers can perform the name resolution, the query fails.

A Name Server can be master for some zones and slave for others or can be only a master, or only a slave, or can serve no zones and just answer queries via its cache, or may act as forward nameserver for others.