Domain Name System (DNS) is used to organize computers and network services in a hierarchy of domains. DNS is used to locate services and computers via user friendly names in TCP/IP networks. It makes the use of network origins easier. It helps in mapping user friendly name for a service or a computer for other information related with it like an IP address.
The question often comes into mind why DNS? Well, these server help client computers in using name to identify the remote hosts instead of struggling with the numeric IP. The name of the distant host is send to the DNS server by the client computer and DNS server reacts with the corresponding IP address. The client computer is thus capable of sending messages directly to the IP address of remote host. There is also a possibility that the entry of remote host made by the client computer is not in the database of the DNS then it is programmed to either send the address of another DNS (that has the information of the remote host) to the client or to enquire other DNS. The process goes on until the DNS either avail the IP address or is informed (n response to its queries) that the inquired name is not of any host existing within a certain DNS namespace.
It is the basic requirement of TCP/IP to have access to at least one DNS server to keep up its operations smooth. The access of client to the remote host will be very tough in the absence of DNS server as there will be no name resolution and other significant services. It will be impossible to browse World Wide Web (WWW) without DNS as the hypertext links make use of the DNS names of web host instead of their respective IP addresses.
A set of name servers (also called default name servers) is given to each and every domain name that is registered. For a certain host or registrar, these name servers are default and are utilized to keep the domain name alive from the very beginning.
For setting up a default DNS records you can create a host record with the name of some asterisk and prescribed an IP (Internet Protocol) to which you want your DNS to return as a result of default domain resolution request.
It is observed that a number of people just register a domain and before they can decide what they are going to make of it, they leave it with the default name server settings of the registrar. This is just because of this reason that default pages are created by a number of registrars that serve as a web site as long as the domain name is using he default name servers.
Cyber-squatters, those who register domain names that look like some famous trademark with their vicious intention to attract web surfers to visit the web page and buy goods at as high a price as of the original trademark, use the DNS settings provided by the registrars.
Wildcard DNS helps in keeping a record of all those host addresses that were asked and have no IP records against them; do not exist can be set up to point out certain address. Let me illustrate it. You can produce some hosts that not at all exist but are associated with your domain. These hosts will point out at a certain IP address so a valid response to the existing host can be returned if any of the surfer request for the address. In short, DNS has made the search of domains more and more user friendly.