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What are NIS and NIS+?
What are NIS and NIS+?
Next: How NIS works Up: NIS NIS+ Previous: NIS NIS+
What are NIS and NIS+?
The Network Information Service (NIS) provides a simple network lookup service consisting of databases and processes. It was formerly known as Sun Yellow Pages (YP). The name had to be changed when British Telecom claimed to have the copyright of this term, and so it became NIS. The functionality of the two remains the same; only the name has changed. Its purpose is to provide information, that has to be known throughout the network, to all machines on the network. Information likely to be distributed by NIS is:
- login names/passwords/home directories (/etc/passwd)
- group information (/etc/group)
- host names and IP numbers (/etc/hosts)
NIS+ (Network Information Service Plus) was introduced by Sun Microsystems with the Solaris 2.x OS. It is compatible with NIS, but has a lot of additional features. With NIS+ it is possible to have hierarchical domains. All changes are done in the NIS+ database, it is not longer necessary to make changes on source files and to rebuild the complete maps. All changes are logged, so that a replica server can sync if it was down for some time.
The choice between NIS and NIS+ is easy - use NIS+ only if you have severe security needs. NIS+ is _much_ more problematic to administer (it's pretty easy to handle on the client side, but the server side is horrible). Another problem is that the support for NIS+ under Linux contains a lot of bugs and that the development has stopped.
NIS benefits users because it improves ease of use of a network. Without NIS, having a large number of systems on the network can create problems for the user. The user would need to remember a different password for every system they use, or else maintain the same password for every system themselves, and update their password on each system separately.
NIS benefits system administrators because it improves ease of administration of a network. NIS reduces the effort of maintaining a large number of systems and provides a global user ID (UID) and group ID (GID) name space. Suppose you are using NFS to make the user's directories and files available on every system. Because NFS does not try to translate UIDs or GIDs between systems, you must ensure that each user in the network has the same user ID and group ID on every system. For example, a user on a workstation whose UID is 205 and whose GID is 35 must have the same UID and GID (205 and 35) in the /etc/passwd file on every workstation that user accesses. If this is not done, a user on one system who creates a file and logs into another system may find that the file is owned by another user.
Next: How NIS works Up: NIS NIS+ Previous: NIS NIS+
2005-05-04