Final answer:
The two main types of DNS zones are the Primary DNS zone, which holds authoritative and editable DNS records for a domain, and the Secondary DNS zone, which contains a read-only copy for redundancy purposes.
Step-by-step explanation:
The two main types of DNS zones are the Primary DNS zone and the Secondary DNS zone. The Primary DNS zone is the authoritative source of information for a certain domain, holding the master copy of data for the domain's DNS records. It allows changes to be made to DNS entries, which are then propagated to other DNS servers. On the other hand, the Secondary DNS zone holds a read-only copy of the domain's DNS records. This copy is acquired through a process called zone transfer from the Primary DNS zone. Secondary zones serve as a redundancy mechanism, handling DNS queries to balance the load and improve the availability of the DNS service.