One very common misconception, and a source of a great deal of confusion, is the relationship between servers and zones. Zones exist on servers. A zone on a particular server can be configured to act as a master zone or a slave zone. A server with a slave zone will periodically update that slave zone with information from a server configured to act as a master for that zone.

DNS servers can serve hundreds or even thousands of zones, some of which can be configured as master, and some as slave. When reference is made to a "Master Server" that only means a server that has been configured to act as a master for a particular zone.