Finctionality of Internet

Domain Name

A domain name is a way to identify and locate computers connected to the Internet. A domain name must be unique; no two organizations on the Internet can have the same domain name.

A typical domain name consists of a second-level domain and a top-level domain, such as "bigco.com". In addition, hostname and subdomain information can be added, for example: "tiger.newyork.bigco.com".

The top-level domain name describes the type of organization or the country with the domain name (EDU, COM, GOV, UK, etc.).

• A way to identify computers Hierarchical Unique A corresponding IP address

A domain name is a way to identify and locate computers connected to the Internet. No two organizations can have the same domain name. A domain name always contains two or more components separated by periods, called "dots".

Some examples of domain names are:

• java.net • ebizel.com • nasa.gov • utexas.edu • reston.va.us

Once a domain name has been established, "subdomains" can be created within the domain.

. For example, the domain name for a large company could be "bigco.com" and within this domain, subdomains can be created for each of the company's regional offices. The structure for this is:

hostname.subdomain.second-level domain.top-level domain For example, java.education.ebizel.com

describes a single host computer named tiger, in the New York office of the Bigco Company. Not all domain names will have a hostname and subdomain. In addition, more than one subdomain can be assigned.

The top-level portion of a domain name describes the type of organization holding that name. The major categories for top-level domains are:

• COM - commercial entities EDU - four year colleges and universities NET - organizations directly involved in Internet operations, such as network providers and network information centers ORG - miscellaneous organizations that don't fit any other category, such as non-profit groups GOV - United States Federal Government entities MIL - United States military

COUNTRY CODES - a two letter abbreviation for a particular country. For example, "UK" for United Kingdom or "FR" for France.

Each domain name corresponds to numeric IP (Internet Protocol) addresses. An IP address takes the form of 4 numbers, each one between 0 and 255, separated by periods.

The Internet uses the numeric IP address to send data. For instance, you may be connecting to a World Wide Web server with the domain name "rs.internic.net", but as far as the network is concerned, you are connecting to the Web server with the IP address associated with that domain name.

The Domain Name System completes the task of matching domain names to IP (Internet Protocol) addresses. Domain names, and their corresponding IP addresses, must be unique.

If more than one organization on the Internet had the same domain name, confusion would occur when the network tried to identify and communicate with the computers within those organizations.

For example, if there were two separate universitites, one in Maine and one in Arizona, they cannot both use the domain name "coolschool.edu", because the Domain Name System would not know which one of the universities' IP addresses were associated with that domain name.

The Domain Name System is a collection of databases that contain information about domain names and their corresponding IP addresses. Domain name servers are computers that translate domain names to IP addresses.

This system allows Internet users to deal with the more intuitive domain names, rather than having to remember a series of numbers.