Definition of "Fully Qualified Domain Name"

A Fully Qualified Domain Name (FQDN) is the complete name of a website address. This name is typed into the browser window address bar at the top of the page to direct the browser to find the website address, then to display that page within the browser window.

Features

Website addresses do not actually consist of the names we type into the address bar. Computers use numbers as their language, and when locating a website, the words typed into the browser bar are translated into the IP (Internet Protocol) address by DNS (Domain Name System) servers to help the browser find the destination address. The Fully Qualified Domain Name consists of a top-level domain name, a second-level domain name and a server name or sub-domain string. When typed into the address bar, these sections are separated by a dot or period.

Top Level Domain Name

For example, the (fictitious) FQDN "www.company.com" is broken down into three sections and is read from right to left. The top-level domain name is the section that appears last. In this example, the "com" stands for commercial; most businesses use this domain. Some of the other top-level domain names include edu (educational), gov (government), int (international), mil (military) and org (non-profit organization).

Second and Third Segments

In the www.company.com example, the second-level domain name is the word "company." This refers to the actual company's name or the name of the website. The final section refers to the server name or the sub-domain string. The "www" stands for the World Wide Web, and indicates to the browser that it will be locating an HTTP server.

Warning

When typing in the FQDN to reach a certain website or webpage, it is necessary to type the address accurately. The DNS servers cannot translate or resolve the words into the correct number address unless the words and format are exactly correct.

FQDN's Connection to URLs

A Fully Qualified Domain Name is similar to a URL (Uniform Resource Locator), but the URL includes another section that designates the protocol for communication between a Web server and the Web browser. It includes terms such as "http" (Hypertext Transfer Protocol, which is the Web's standard communications protocol), "https" (HTTP secure, used for sites that need security, such as banks and sites that accept online payments) or "ftp" (File Transfer Protocol, used for transferring files). This term is typed to the left of the other three sections, followed by a colon and two forward slashes. Our example would then be typed: "http://www.company.com."

Current Browser Requirements

When the World Wide Web began in 1991, it was necessary to include the entire URL address, using the "http" section and the "www" section. Currently, most browsers do not require users to type those sections. But it is useful to be aware of them in case they are required by some browsers or for certain sites.

References

• "Computer Concepts 2010"; June Jamrich Parsons, Dan Oja; 2010
• "Network+ Study Guide Deluxe Edition"; David Groth, Toby Skandler, Todd Lammie, William Tedder; 2005
• "Sam's Teach Yourself Networking in 24 Hours"; Joe Habraken, Matt Hayden; 2004