NIS+ stores information in tables instead of maps or zone files. NIS+ provides 16 types of predefined, or system, tables, which are named in the following list:
Hosts
Bootparams
Password
Cred
Group
Netgroups
Mail Aliases
Timezone
Networks
Netmasks
Ethers
Services
Protocols
RPC
Auto_Home
Auto_Master
Each table stores a different type of information. For instance, the Hosts table stores host name/Internet address pairs, and the Password table stores information about users of the network.
NIS+ tables have two major improvements over NIS maps. First, a NIS+ table can be accessed by any column, not just the first column, which is sometimes referred to as the “key.” This access eliminates the need for duplicate maps, such as the hosts.byname and hosts.byaddr maps of NIS. Second, access to the information in NIS+ tables can be controlled at three levels of granularity: the table level, the entry level, and the column level.