DNS - Domain Name System

DNS or domain name system is used to identify the computer in the network. Although computers work at their best when dealing with numbers, humans feel more at home dealing with names. For instance, you would certainly prefer someone asking you to send a message to Albert's computer than telling you to send it to a computer whose IP address is 150.21.90. 101. (This, however, is much better than having to talk about an address as a string of 32 bits.) Albert's computer might correspond to this IP address. But for you, it is far better to call it Albert's computer, or even better, simply Albert! This simple idea of identifying computer networks and computers on those networks by some names is the basis for domain names.

A domain name is a name given to a network for ease of reference by humans. The term domain actually refers to a group of computers that are known by a single common name. Of course, somebody ultimately has to translate these domain names into IP addresses, because it is only this 32 bit IP addresses of computers that the TCP/IP or the Internet understands while sending or receiving any messages such as emails or files.

People often name their computers with pride. In some organizations, naming computers is standardized. But in many other cases, computers are identified by the names of the people that use them, or by planet names. You might then hear a comment such as Amy is down today, which actually means that Amy's computer is not working for some reason! In short we humans like to call computers by names. There is only one problem here. Two computers in a network cannot have the same name. Otherwise, a computer cannot be identified uniquely. For this reason, it is necessary to ensure that the computer names are always unique and that too globally, if we want to use them on the Internet. DNS uses this same naming system.

In order to make computer names unique, the Internet naming convention uses a simple idea. Additional strings or suffixes are added to the names. The full name of a computer consists of its local name followed by a period and the organization's suffix. For example, if Harry works in IBM, her computer's name would be Harry. IBM. Of course, if there are two or more persons with the same name in an organization, another convention (e.g. Harry I and Harry2 in this case) could be used.

This however, is not good enough. The names of the organizations themselves could be same or similar. For example, Harry.techsystems may not suffice, since there can be many organizations with the name techsystents. (Moreover, there could be many Alberts in each of them). This means, having the organization's suffix to the local name is not adequate. As a result, another suffix is added to the computer names after the organization' s name. This indicates the type of the organization. For example, it could be a commercial organization, a non profit making concern or a university. Depending on the type, this last suffix is added. Normally, this last suffix is three characters long. For example: com indicates a commercial organization, edu indicates an university and net indicates a network. As a result, Harry's computer would now become Harry.IBM.com. In general terms, all computers at IBM would have the last portion of their names as IBM.com. Thus if an IBM university were to come up, it would not clash with IBM.com. Instead, it would become IBM.edu.

It must be mentioned that a computer's name on the Internet need not necessarily be made up of only three parts. Once the main portion of the name is allocated to an organization (e.g. IBM.com), the organization is free to add further sub names to computers. For instance, IBM's US division might choose to have a prefix of IBM-US.com or IBM.US.com to all their computers instead of IBM.com.

Country Specific DNS

Generic Domain Names

com - Commercial organization
edu- Educational institution
gov- Government institution
int- International organization
mil- Military group
net- Network support group
org- Non-profit organization

Domain Name Search