Domain names are subject to the following conditions in their structure:
The only valid characters for a domain name are the letters of the alphabet (A-Z), the digits (0-9), and the dash (-). It is not allow letters with accent, nor underlined. There is no distinction between capital letters and lower case letters. The first and last character of the domain cannot be a dash, as well as two or more followed dashes cannot exist.
The required minimum length is of 3 characters and the maximum length is of 65 characters. Although technically it is allowed up to 65 characters, it is recommendable that the maximum is of 25 characters for practical reasons.
Let's look in more detail at a domain name, using this site's domain name as an example. This site's domain name is cheap-webdesign.com - you can check this easily by looking at in the URL or location bar of your browser.
.com is the top domain under which my domain name is registered. There are heaps of different top domains out there, from commercial (.com) through to non-profit (.org) and even country-specific top domains such as France (.fr) and Italy (.it). Every domain name is registered under a top domain of some kind. The top domain is often known as the domain extension - these are the same thing, so don't get mixed up!
The majority of domain names are comprised of three parts, separated by periods, for example: www.unc.edu. The first component of the domain name identifies the server, which is used to access the particular site. Thus, in our example, " www " identifies the World Wide Web server. The second part denotes a source-identifying designation selected by the user, known as the second-level domain name. It should be noted; users could further distinguish their Internet address by adding lower level of domain names, to further specify the location of the host computer. For example, the University of North Carolina could provide its departments with their own domain names such as " www.law.unc.edu. " Here, " Law " represents a third-level domain name. The last element of a domain name is known as the top-level domain ( " TLD " ) name. Each TLD identifies the classification of user who has registered the domain name.
Here are a few examples of domain names that you may already be familiar with. They belong to well-known companies or organizations.
ibm.com
apple.com
whitehouse.gov
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