Oracle Solaris Naming Services

The Oracle Solaris platform provides the following naming services:

• Domain Name System (DNS) (see Description of the DNS Naming Service)

• /etc files, the original UNIX naming system (see Description of the /etc Files Naming Service)

• Network Information Service (NIS) (see Description of the NIS Naming Service)

• Lightweight Directory Access Protocol (LDAP) (see Part III, LDAP Naming Services LDAP Naming Services Setup and Administration)

Most modern networks use two or more of these services in combination. Which naming service is used for a particular lookup is coordinated by the name service switch, which is discussed in Chapter 2, Name Service Switch (Overview).

Description of the DNS Naming Service

The Domain Name System (DNS) is a hierarchical, distributed database, implemented on a TCP/IP network. It is primarily used to look up IP addresses for Internet host names and host names for IP addresses. The data is distributed across the network and is located by using period-separated names that are read from right to left. DNS is also used to store other Internet-related host information, such as mail exchange routing information, location data, and available services. The hierarchical nature of the service enables the local administration of local domains, while providing international coverage of other domains connected that are to the Internet, an intranet, or both.

DNS clients request information about a host name from one or more name servers and wait for a response. DNS servers respond to requests from a information cache that was loaded from file or a third-party database on a DNS master, or over the network from a cooperating DNS slave server, or from information stored from previous queries. If no response is found and the server is not responsible for the domain in question, the service will, if so permitted, recursively request the host name from other servers and cache that response.

Description of Multicast DNS and Service Discovery

Two extensions to the DNS protocol are managed by the svc:network/dns/multicast service. Multicast DNS (mDNS) implements DNS in a small network where no conventional DNS server has been installed. DNS Service Discovery (DNS-SD) extends Multicast DNS to also provide simple service discovery (network browsing). For more information, see Multicast DNS and Multicast DNS Service Discovery.

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Caution - The mDNS service uses the .local domain name, so that name should not be also used in DNS to avoid possible conflicts.

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Description of the /etc Files Naming Service

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 manage all naming data by using only local files. However, managing hosts, users, and other naming data by using local files is not well suited for large complex networks. Each /etc file is described in its associated man page. For example, the /etc/inet/hosts file is described in the hosts(4) man page.

Description of the NIS Naming Service

The Network Information Service (NIS) was developed independently of DNS. DNS makes communication simpler by using machine 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 the network, machine names and addresses, users, 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. NIS maps store much more than names and addresses. As a result, the NIS namespace has a large set of maps. See Working With NIS Maps for more information.

NIS uses a client-server arrangement which is similar to DNS. Replicated NIS servers provide services to NIS clients. The principal servers are called master servers, and for reliability, the servers have backup, or slave servers. Both master and slave servers use the NIS retrieval software and both store NIS maps. For more information on NIS Architecture and NIS Administration, see Chapter 6, Setting Up and Configuring NIS (Tasks) and Chapter 7, Administering NIS (Tasks).

Description of the LDAP Naming Services

The Lightweight Directory Access Protocol (LDAP) is the secure network protocol used to access directory servers for distributed naming and other directory services. This standard based protocol supports a hierarchal database structure. The same protocol can be used to provide naming services in both UNIX and multi-platform environments.

The Oracle Solaris OS supports LDAP in conjunction with the Oracle Directory Server Enterprise Edition (formerly Sun Java System Directory Server), as well as other LDAP directory servers.

For information about LDAP naming services, see Chapter 9, Introduction to LDAP Naming Services (Overview).

For information about transitioning from NIS to LDAP, see Chapter 15, Transitioning From NIS to LDAP (Tasks).

For information about single sign-on, as well as the setup and maintenance of Kerberos authentication services, see Part VI, Kerberos Service, in Oracle Solaris 11.1 Administration: Security Services.

Description of the Name Service Switch

The name service switch is a mechanism to allow clients to search through the DNS, LDAP, NIS or local files data sources for naming information. The switch is managed through the svc:/system/name-service/switch service. For more information, see Chapter 2, Name Service Switch (Overview).