- We have established that web domains are found as part of URLs. So what are URLs? Simply put, URLs are web addresses that identify specific web pages. A URL is what you type into your browser in order to reach a specific location on the Internet.
- The Internet resides on multiple computers around the world. The computers identify each other not by words, but by numbers. These numbers are referred to as Internet Protocol, or IP, addresses. The average person would have a hard time remembering various IP addresses. So in order to make the task a little easier for non-computer brains, words are used. Domain names are then translated into IP addresses by a Domain Name System (DNS) server.
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Domain names have a hierarchy. Most Internet users are familiar with these common top level domains: ".com" and ".net." Two other commonly used top level domains are ".edu" and ".gov." The ".com" domain is for commercial businesses; the ".edu" is for educational organizations and the ".mil" is for the military. The level to the left of a top level domain is called the second-level domain. The level to the left of that is called the third-level domain. Each successive sub domain is named fourth, fifth, sixth.
Here is an example: mail.google.com. The "google" is the second-level domain. The "mail" portion is the third-level domain. - Domain names can neither exceed 255 characters nor contain spaces. Web domains can use the letters "A" through "Z" (ASCII, non-case sensitive) and the digits 0 through 9. Hyphens may also be used as long as they are not used at the beginning or the end.
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The Internet Corporation for Assigned Names and Numbers manages the Domain Name System.
Country-level domain registries are managed by their respective government agency. See the Resources section for more information on the ICANN.
