services.hickory-dns.settings.zones.*.zone_type

One of:

• "Primary" (the master, authority for the zone).
• "Secondary" (the slave, replicated from the primary).
• "Hint" (a cached zone with recursive resolver abilities).
• "Forward" (a cached zone where all requests are forwarded to another resolver).

For more details about these zone types, consult the documentation for BIND, though note that hickory-dns supports only a subset of BIND's zone types: https://bind9.readthedocs.io/en/v9_18_4/reference.html#type.