NIS+ is a directory service developed by Sun Microsystems to replace its older 'NIS' (Network Information Service). It is designed to eliminate the need for duplication across many computers of configuration data such as user accounts, host names and addresses, printer information and NFS disk mounts on individual systems, instead using a central repository on a master server, simplifying system administration. NIS+ client software has been ported to other Unix and Unix-like platforms. Prior to the release of Solaris 9 in 2002, Sun announced its intent to remove NIS+ from Solaris in a future release and now recommends that customers instead use an LDAP-based lookup scheme. NIS+ was present in Solaris 9 and 10 (although both releases include tools to migrate NIS+ data to an LDAP server) and it has been removed from Solaris 11. NIS vs. NIS+ NIS and NIS+ are similar only in purpose and name, otherwise, they are completely different implementations. They differ in the following ways: NIS+ is hierarchical. NIS+ is based around Secure RPC (servers must authenticate clients and vice versa). NIS+ may be replicated (replicas are read-only). NIS+ implements permissions on directories, tables, columns and rows. NIS+ also implements permissions on operations, such as being able to use to transfer changed data from a master to a replica. The problem of managing network information In the 1970s, when computers were expensive, and networks consisted of a small number of nodes, administering network information was manageable, and a centralized system was not needed. As computers became cheaper and networks grew larger, it became increasingly difficult to maintain separate copies of network configurations on individual systems. For example, when a new user was added to the network, the following files would need to be updated on every existing system: Likewise, would have needed updating every time a new group was added and would have needed updating every time a new computer was added to the network. If a new user with a new system was added to a network of 20 existing systems, the UNIX administrator would need to modify 5 files on 21 machines - 105 files in all. With NIS+, adding users and machines to the network requires changes only to the NIS+ server's maps and the new host's /etc/nsswitch.conf needs to point to the NIS+ server. When a user logs into any other machine, that host (the NIS+ client), knowing who the NIS+