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NIS and NIS+ Compatibility

NIS+ provides an NIS compatibility mode. This mode lets an NIS+ server running Solaris 2.x system software answer requests from NIS as well as NIS+ clients. When the NIS+ server is set up, the NIS compatibility mode can be selected. You do not need to do any additional setup or changes for the NIS client. The NIS+ compatibility mode is one way that you can gradually make the transition from NIS to NIS+.

Another way that you can ease the transition is to set up a Solaris 1.x server to act as an NIS+ server. To accomplish this task, you must install the NIS+ SunOS 4.1 distribution on the Solaris 1.x server. The NIS+ SunOS 4.1 distribution permits Solaris 1.x servers to act as NIS+ servers without an upgrade to Solaris 2.x. The Solaris 2.x CD-ROM contains a complete set of SunOS 4.1.x NIS+ executables that you can install on a SunOS 4.1.x system. The executables are in a separate tar file in the root directory of the Solaris 2.x CD-ROM. You must manually install the NIS+ files, following the instructions in the readme file provided on the CD-ROM. You cannot install the NIS+ files on a SunOS 4.1.x system using SunInstall.

Table 5-7 shows a matrix of possible configurations between clients and servers. The additional rows and columns for ONC NIS systems are included because many customers have ONC NIS name servers from vendors other than SunSoft.

Table 5-7 NIS/NIS+ Compatibility

Server NIS+ NIS+ NIS
SunOS 5.x SunOS 4.x Any ONC NIS
SunOS 5.x Supported Supported Supported*
SunOS 4.x Supported**Supported**Supported
Any ONC NIS Supported**Supported**Supported

*client must specify nis in the /etc/nsswitch.conf file. The SunOS client system can run ypbind and access the ONC NIS system.
**NIS+ server must run in NIS compatibility mode (-Y option).

The comparison between master servers and slave servers is as follows: NIS master servers know about NIS slave servers only; NIS does not know about NIS+. NIS+ master servers interact with NIS+ replica servers only. NIS+ does not convert NIS+ tables into maps and push them to NIS slave servers.

The Name Service Switch

Solaris 2.x provides a new name service switch file, /etc/nsswitch.conf, that you can use to tailor the name service policy of individual systems to use multiple name services in the Solaris 2.x environment. With the /etc/nsswitch.conf file, you can specify the following:

  Which name service(s) is used for each type of configuration information, such as password or host IP address
  The order in which the different name services are used for each type of information
  The criteria for search continuation if information is not found or if a name service is not available

You can use the /etc/nsswitch.conf file to set flexible policies for name service use and to describe and change these policies after site requirements change. For example, a system running the Solaris 2.x environment could obtain its host’s information from an NIS+ table, its group information from NIS maps, and its password information from a local /etc file.

The /etc/nsswitch.conf file also simplifies migration from NIS to NIS+, as both Solaris 1.x and Solaris 2.x systems can be clients of Solaris 1.x NIS servers. In addition, Solaris 2.x systems can be clients of both NIS and NIS+, which allows the two name services to coexist during the transition. If you combine NIS and NIS+ domains, make sure that they both use the same domain name.

When you install Solaris 2.x system software, the /etc directory contains a default nsswitch.conf file and the files nsswitch.files, nsswitch.nis, and nsswitch.nisplus, which provide default settings for each of these possible sources of name service information: files, NIS, and NIS+, respectively. An example of the default nsswitch.nisplus file is included in Chapter 6.

When you set up an NIS+ server or client system, you must copy the /etc/nsswitch.nisplus file to /etc/nsswitch.conf. After you have copied the file, you can either use the default file or customize it to suit the needs of your site. SunSoft suggests that you start by using the default file and customize it only if you need to do so.

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