server is, queries it for the username and password to identify and authenticate the user. NIS+ also manages several other types of data: NFS mounts (auto_master, auto_home), network booting and other parameters (bootparams, ethers, netmasks, netgroup, networks, protocols, rpc, services), security access (cred), aliases, and time zone. An installation of NIS+ comes with such table structures predefined. There are facilities available to create other tables as needed. Alternatives Other alternative schemes for storing network information exist, such as the LDAP standard maintained by the IETF, including Microsoft's LDAP implementation, Active Directory. LDAP can be configured to handle more general information, such as corporate employee structures, phone numbers, address, etc. so it requires more thought and planning. Many organizations require all the features of NIS+, LDAP, and Active Directory and run them all simultaneously. Another alternative that has been popular in certain environments is the Hesiod name service, which is based on the DNS protocols. NIS+ client/server model Unlike NIS, NIS+ uses a hierarchical structure of multiple domains. A NIS+ domain can, and should, be serviced by multiple servers. The primary server is known as the master server, and backup servers are known as replica servers. Both types hold copies of the NIS+ tables. Changes are first committed to the master server and then propagated to replica servers in increments. NIS+ table permissions determine a user's level of access to the table's contents. See also client–server model Lightweight Directory Access Protocol (LDAP) Network Information Service (NIS) References External links Resources on how to replace NIS and NIS+ can be found at the NIS Migration Resource Site Unix network-related software Sun Microsystems software Network management Directory services