The Solaris operating environment provides the following name services:
DNS, the Domain Name System (see "DNS").
/etc files, the original UNIX naming system (see "/etc Files").
NIS, the Network Information Service (see "NIS").
NIS+, the Network Information Service Plus (see "NIS+").
FNS, the Federated Naming Service, supports the use of different autonomous naming systems in a single Solaris environment (see "FNS").
Most modern networks use two or more of these services in combination. When more than one service is used, they are coordinated by the nsswitch.conf file which is discussed in Chapter 2, The Name Service Switch.
DNS, the Domain Name System, is the name service provided by the Internet for TCP/IP networks. It was developed so that workstations on the network could be identified with common names instead of Internet addresses. DNS performs naming between hosts within your local administrative domain and across domain boundaries.
The collection of networked workstations that use DNS are referred to as the DNS namespace. The DNS namespace can be divided into a hierarchy of domains. A DNS domain is simply a group of workstations. Each domain is supported by two or more name servers: a principal server and one or more secondary servers. Each server implements DNS by running a daemon called in.named. On the client's side, DNS is implemented through the "resolver." The resolver's function is to resolve users' queries; to do that, it queries a name server, which then returns either the requested information or a referral to another server.
The original host-based UNIX naming system was developed for stand-alone UNIX machines and then adapted for network use. Many old UNIX operating systems and machines still use this system, but it is not well suited for large complex networks.
The Network Information Service (NIS) was developed independently of DNS and has a slightly different focus. Whereas DNS focuses on making communication simpler by using workstation names instead of numerical IP addresses, NIS focuses on making network administration more manageable by providing centralized control over a variety of network information. NIS stores information about workstation names and addresses, users, the network itself, and network services. This collection of network information is referred to as the NIS namespace.
NIS namespace information is stored in NIS maps. NIS maps were designed to replace UNIX /etc files, as well as other configuration files, so they store much more than names and addresses. As a result, the NIS namespace has a large set of maps (see "NIS Maps").
NIS uses a client-server arrangement similar to DNS. Replicated NIS servers provide services to NIS clients. The principal servers are called master servers, and for reliability, they have backup, or slave servers. Both master and slave servers use the NIS information retrieval software and both store NIS maps. For more information on NIS Architecture, see "NIS Architecture".
See Part IVAdministering NIS for more information about NIS and how to administer it.
The Network Information Service Plus (NIS+) is similar to NIS but with many more features. NIS+ is not an extension of NIS. It is a new software program.
The NIS+ name service is designed to conform to the shape of the organization that installs it, wrapping itself around the bulges and corners of almost any network configuration. Unlike NIS, the NIS+ name space is dynamic because updates can occur and be put into effect at any time by any authorized user.
NIS+ enables you to store information about workstation addresses, security information, mail information, Ethernet interfaces, and network services in central locations where all workstations on a network can have access to it. This configuration of network information is referred to as the NIS+ namespace.
The NIS+ namespace is hierarchical, and is similar in structure to the UNIX directory file system. The hierarchical structure allows an NIS+ namespace to be configured to conform to the logical hierarchy of an organization. The namespace's layout of information is unrelated to its physical arrangement. Thus, an NIS+ namespace can be divided into multiple domains that can be administered autonomously. Clients may have access to information in other domains in addition to their own if they have the appropriate permissions.
NIS+ uses a client-server model to store and have access to the information contained in an NIS+ namespace. Each domain is supported by a set of servers. The principal server is called the master server and the backup servers are called replicas. The network information is stored in 16 standard NIS+ tables in an internal NIS+ database. Both master and replica servers run NIS+ server software and both maintain copies of NIS+ tables. Changes made to the NIS+ data on the master server are incrementally propagated automatically to the replicas.
NIS+ includes a sophisticated security system to protect the structure of the namespace and its information. It uses authentication and authorization to verify whether a client's request for information should be fulfilled. Authentication determines whether the information requester is a valid user on the network. Authorization determines whether a particular user is allowed to have or modify the information requested. See Chapter 6, Security Overview for a more detailed description of NIS+ security, and Chapter 8, Administering NIS+ Keys for information on administering NIS+ security.
FNS, the Federated Naming Service, supports the use of different autonomous naming systems in a single Solaris environment. FNS allows you to use a single, simple naming system interface for all of the different name services on your network. FNS conforms to the X/Open federated naming (XFN) specification.
FNS is not a replacement for NIS+, NIS, DNS, or /etc files. Rather, FNS is implemented on top of these services and allows you to use a set of common names with desktop applications.
See Part VAdministering FNS for more information about FNS and how to administer it.