What is Domain in DNS & Domain in NIS | DNS & NIS Concepts

NIS(Network Information Service)

NIS (Network Information Service) focuses on making network administration manageable by providing centralized control over a variety of network information.

NIS stores information not only about host names and addresses, but also about users, the network itself, and network services, This collection of network information is referred to as the NIS namespace.

Using NIS, you can maintain a single set of configuration files for a collection of computers in an NIS server. All other computers running NIS clients can then access the files, For example – if your user name and password are in the NIS password database, you will be able to log in on all computers on the network running NIS.

If you want to use NIS in a network, you must set up at least one NIS server. You can have multiple NIS servers in a network, each serving a different collection of computers. You can also have a master NIS server and one or more slave NIS servers that receive a copy of the master’s database. The group of computers a master NIS server supports is called an NIS domain or YP domain.

Domain in NIS

An NIS domain cannot be connected directly to the Internet using just NIS. However, organizations that want to use NIS and also be connected to the Internet can combine NIS with DNS.

You can use NIS to manage all local information and use DNS for Internet host lookup. NIS also provides a forwarding service that forwards host lookups to DNS if the information cannot be found in an NIS map.

NIS uses a client-server arrangement. NIS servers provide services to NIS clients. The principal server is called a master server, and for reliability, it can have several backup servers or slave servers or Secondary Server. Both master and slave servers use the NIS information retrieval software, and both store NIS maps.

The NIS domain name identifies the group of computers that a particular NIS server supports.

DNS(Domain Name System)

DNS is a distributed, hierarchical database that holds information includes the hostname, the IP address, and mail routing information.

The primary job of DNS is to associate hostnames to IP addresses and vice versa, DNS uses a hierarchical tree of domains to organize the namespace-the entire set of names. Each higher-level domain has authority over its lower-level subdomains. Each domain represents a distinct block of the namespace and is managed by a single administrative authority.

The DNS(Domain Name System)hierarchy, is pictured as an inverted tree, with the root node at the top –

DNS Hierarchy

DNS uses a hierarchical tree of domains to organize the namespace-the entire set of names. Each higher-level domain has authority over its lower-level subdomains. Each domain represents a distinct block of the namespace and is managed by a single administrative authority.

Here in above figure ,

berkeley has three subdomain - cs , co & me
                             -> cs.berkeley.edu
                             -> co.berkeley.edu
                             -> me.berkeley.edu

One more thing to noted as discussed above, “berkeley.edu” could be managed by some other Organization & their subdomain like “cs.berkeley.edu” could be managed by different organization for different purposes.

In above figure , as you could see “edu” denotes education , and the depth of above tree could go to 127 .