What is a Domain?: Domain Name Basics

All computers have a unique Internet Protocol, or IP, address. Essentially, this is a number that is given to each and every computer. It is like both a home address and a fingerprint. No two IP addresses are exactly the same.

An IP address is presented in decimal format with numbers ranging from 0 to 255. To better identify the IP address, a person must know what to look for. An IP address looks like this: 64.58.91.254.

Essentially, a domain name is identical to an IP address. IP addresses are domain names that people can easily read and comprehend. For instance, Google.com is far easier to remember than 64.233.167.99.

All domain names are a combination of numbers, letters and/or hyphens. Special characters such as &, $ or * are not allowed. If a person or business wants to create a site, he/she must have a domain name to get started. When a person registers his/her domain, it will directly correspond to their own personal IP address.

Domain Levels

In addition to simply choosing a name for the site itself, the domain levels must be considered. There are three levels of domains. Domains on the top level are most commonly used.

These domains are divided into three categories: 

• Generic
• Country code
• Infrastructure

Generic top-level domains are the domains that you would normally see when surfing the internet. These consist of:

• .com- used by commercial organizations, available to the public
• .net- used by sites related to the internet, available to the public
• .org- used for non profit organizations, available to the public
• .edu- used by educational organizations, not available to the public
• .gov- reserved for government agencies, not available to the public
• .mil- reserved for the US military, not available to the public
• .biz- used only by businesses, not available to the general public
• .coop- reserved for cooperative organizations, not available to the general public
• .name- reserved for individuals, available to the public

Country code domains are used to designate a country. For example: you may see .uk at the end of a domain name. This is used to represent the United Kingdom.

Infrastructure domains are limited to .arpa. This domain is used exclusively by the government agency that developed the internet The United States Department of Defense Advanced Research Projects Agency, or ARPA.

Second level domains come right after the dot in the top level domains. Examples of second level domains are .co.uk, .edu.uk, .org.au, and .net.uk.

Third level domains come prior to first level domains. These are usually sub domains like: www.johndoe.hostname.com. These are generally used on free hosting packages.

Here’s a quick breakdown of http://johndoe.tripod.com.uk:

1. john doe- third level or sub domain
2. Tripod- first level domain
3. com.uk- second level domain

In short, a domain name is what distinguishes one website from another. Make sure that the name you choose is not too complicated to spell or remember. Also, be sure that this name cannot be mistaken for anything questionable. Understanding domain names is the key to choosing the right one for your business or organization.

source : http://smallbusiness-domain.com