Editing Network Information Service

{{Short description|Directory service protocol from Sun Microsystems}}
{{more citations needed|date=January 2019}}
The '''Network Information Service''', or '''NIS''' (originally called '''Yellow Pages''' or '''YP'''), is a [[client–server]] [[directory service]] [[protocol (computing)|protocol]] for [[Distributed computing|distributing]] [[system configuration]] data such as [[User (computing)|user]] and [[host name]]s between [[computer]]s on a [[computer network]]. [[Sun Microsystems]] developed the NIS; the technology is [[Software license|licensed]] to virtually all other [[Unix]] vendors.

Because [[British Telecom]] PLC owned the name "[[Yellow Pages]]" as a registered [[trademark]] in the [[United Kingdom]] for its paper-based, commercial [[telephone directory]], Sun changed the name of its system to NIS, though all the commands and functions still start with "yp".<ref>{{cite book|url=https://books.google.com/books?id=daks78g9Pg0C&pg=PA151|title=Automating System Administration with Perl: Tools to Make You More Efficient|author=David N. Blank-Edelman|publisher=[[O'Reilly Media]]|isbn=9780596555634|year=2009|page=151}}</ref>

A NIS/YP system maintains and distributes a central directory of user and group information, hostnames, e-mail aliases and other text-based tables of information in a computer network. For example, in a common [[Unix|UNIX]] environment, the list of users for [[Identification (information)|identification]] is placed in {{mono|[[Passwd (file)|/etc/passwd]]}} and secret [[authentication]] [[Cryptographic hash function|hashes]] in {{mono|/etc/shadow}}. NIS adds another "global" user list which is used for identifying users on any [[Client (computing)|client]] of the NIS domain.

Administrators have the ability to configure NIS to serve password data to outside processes to authenticate users using various versions of the Unix [[Crypt (C)|crypt(3)]] hash algorithms.  However, in such cases, any NIS(0307) client can retrieve the entire password database for offline inspection. 

==Successor technologies==
The original NIS design was seen to have inherent limitations, especially in the areas of scalability and security, so other technologies have come to replace it.

Sun introduced [[NIS+]] as part of [[Solaris (operating system)|Solaris 2]] in 1992, with the intention for it to eventually supersede NIS.  NIS+ features much stronger security and authentication features, as well as a hierarchical design intended to provide greater scalability and flexibility.  However, it was also more cumbersome to set up and administer, and was more difficult to integrate into an existing NIS environment than many existing users wished.  [[NIS+]] was removed from Solaris 11.<ref>{{cite web |url=http://www.oracle.com/technetwork/systems/end-of-notices/eonsolaris11-392732.html |title=End of Feature Notices for Oracle Solaris 11 |date=2012-12-20|publisher=[[Oracle Corporation]]}}</ref>

As a result, many users choose to remain with NIS, and over time other modern and secure distributed directory systems, most notably [[Lightweight Directory Access Protocol]] (LDAP), came to replace it. For example, <code>[[slapd]]</code> (the standalone LDAP [[Daemon (computer software)|daemon]]) generally runs as a non-[[root user]], and [[Simple Authentication and Security Layer|SASL]]-based encryption of LDAP traffic is natively supported.

On large [[LAN]]s, [[Domain name system|DNS]] servers may provide better [[nameserver]] functionality than NIS or LDAP can provide, leaving just site-wide identification information for NIS master and slave systems to serve. However, some functions{{mdashb}}such as the distribution of netmask information to clients, as well as the maintenance of e-mail aliases{{mdashb}}may still be performed by NIS or LDAP.  NIS maintains an [[Network File System (protocol)|NFS]] database information file as well as so called maps.

== See also ==

* [[Dynamic Host Configuration Protocol]] (DHCP)
* [[Hesiod (name service)]]
* [[Name Service Switch]] (NSS)
* [[Network information system]], for a broader use of NIS to manage other system and networks

==References==
{{Reflist}}

==External links==
* {{cite web|url=http://www.tldp.org/HOWTO/NIS-HOWTO/|title=The Linux NIS(YP)/NYS/NIS+ HOWTO|author=Thorsten Kukuk|date=2003-07-01|publisher=[[Linux Documentation Project]]}}
* {{cite web|url=http://www.vanemery.com/DAS/DAS-manual.html|title=Distributed Authentication System (DAS) Handbook|author=Van Emery|date=2005-04-15|url-status=dead|archiveurl=https://web.archive.org/web/20060715144025/http://www.vanemery.com/DAS/DAS-manual.html|archivedate=2006-07-15}}
* {{cite web|url=https://community.broadcom.com/symantecenterprise/communities/community-home/librarydocuments/viewdocument?DocumentKey=1e3cab2f-94cd-4487-a810-fbb863b44954&CommunityKey=1ecf5f55-9545-44d6-b0f4-4e4a7f5f5e68&tab=librarydocuments|title=NFS and NIS Security|author=Kristy Westphal|date=2001-01-22|publisher=[[NortonLifeLock|Symantec]]}}
* {{cite web|url=https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-server_security-securing_nis|title=Red Hat Enterprise Linux 6: 2.2.3. Securing NIS|publisher=[[Red Hat]]}}
* {{cite web|url=http://www.ibiblio.org/pub/Linux/docs/LDP/linuxfocus/English/July2001/article148.shtml|title=Yellow Pages, part 1|author=Frédéric Raynal|date=2001-06-29|publisher=[[ibiblio]]}}
* RHEL 9 will remove support for NIS [https://ostconf.com/system/attachments/files/000/001/693/original/Alexander_Bokovoy.pdf Alexander Bokovoy, Sr. Principal Software Engineer slide show]

{{Sun Microsystems}}

[[Category:Unix network-related software]]
[[Category:Sun Microsystems software]]
[[Category:Network management]]
[[Category:Directory services]]
[[Category:Inter-process communication]]
[[Category:1990 software]]