BIND Configuration File Guide - acl Statement

acl name {
  address_match_list
};

The acl statement creates a named address match list. It gets its name from a primary use of address match lists: Access Control Lists (ACLs).

You must define an address match list's name with acl before you can use it elsewhere; no forward references are allowed.

any

Allows all hosts.

localhost

Allows the IP addresses of all interfaces on the system.

localnets

Allows any host on a network for which the system has an interface.

none

Denies all hosts.