Reference Series Table of Contents For This Issue

How Computers Work, Part I
August 2001• Vol.5 Issue 3
Page(s) 188-193 in print issue

Behind The Domain Name
Secrets Of The Internet Protocol Addressing System
Feeling like a number is more than just a feeling on the Internet. Although your favorite Web site might have a domain name of, the browser software on your computer may look at the same site as As humans, we might prefer to work with names and faces, but computers work more efficiently with numbers.

It can take just seconds to look up and access a Web site through your computer, but what goes on in the background to get you to that site is staggering. Servers contact other network hosts to locate the correct address, and then they pass it along to your Web browser so it can directly contact the appropriate location. And it all starts by simply typing a domain name in the address field of your Web browser.

 From Names To Numbers. The Internet may seem like a huge, incomprehensible monster of wires and connections, but when you break it down, it’s just a big network of connected computers. Similar to other networks, the Internet has servers, which are powerful, main computers, and individual client computers.

The Internet has to follow a set of rules, just as all networks do. And when it comes to addressing, the Internet follows the protocols of the TCP/IP (Transmission Control Protocol /Internet Protocol). Under these rules, each computer on the network is identified as a 32-bit numeric code, called an IP address. IP addresses consist of four groups of numbers separated from each other by periods. One rule for each of these 8-bit groups is that they can’t be greater than 256. An actual IP address looks something similar to The beginning of the IP address tells the routers which network you want to visit. The numbers at the end tell the network which computer you want. The purpose of the two middle sections varies from address to address.

Each computer on the Internet has its own IP address, even your Internet-connected PC at home or work. Although you may be able to determine your own domain name (if it’s available and you pay for permission to use it), you won’t be able to determine your own IP address. Your ISP (Internet service provider), online service, or LIR (local Internet registry) will take care of that for you. These services obtain designated IP addresses from one of three RIRs (regional Internet registries), such as the ARIN (American Registry for Internet Numbers).

Fortunately, we don’t have to remember these numeric codes every time we want to access our favorite shopping site. Instead, we can quickly type a Web address, such as, to see the site display on-screen. Your Web browser and the Internet’s addressing system take care of the translation for you behind the scenes.

Internet developers built name servers into the system that include tables to match domain names, such as, to the correct IP address. Your browser goes through a series of contact points to locate the appropriate name server that holds the domain name and its matching IP address on the Internet.

 Inside A Name. Although site sponsors can determine their own alphanumeric domain name, they also have to play by some rules.

For example, domain names generally consist of 26 characters that can be letters or numbers. You can’t have any empty spaces in a domain name, but you can use hyphens to connect words and phrases as long as you don’t begin or end your domain name with a hyphen. Yes, you might find that some registrars permit you to use up to 63 characters in your domain name, but be wary of doing this. Some Web browsers, e-mail programs, and other Internet applications may not be able to recognize such lengthy domain names. Therefore, it might be better to stick with a shorter version.

To keep things organized, the domain names have a hierarchy. Each portion of a domain name is a domain. The top of the hierarchy, strangely enough, comes at the end of the name. Generic TLDs (top-level domains) typically consist of three letters following a period. TLDs frequently used in the United States include .COM, .EDU, .GOV, .MIL, .NET, and .ORG. Of course, like everything else in the Internet industry, this is changing—and this change is for the better. With the approval of new TLDs, many more choices will soon be available. To find out more about this, skip ahead to the “More Variety, Please” section of this article.

Other countries use their own two-character ccTLDs (country code TLDs), such as .IE for Ireland. For more information, see the “Country Code Extensions: What Do They Mean?” sidebar (in the “How Domain Names Work” two-page graphic included with this article). And if this sidebar doesn't include the ccTLD you’re looking for, you can access IANA's (Internet Assigned Numbers Authority’s) ccTLD database online (http://www.iana .org/cctld/cctld-whois.htm).

The next step down in the hierarchy is the host server name. You might even have a subdomain preceding the host server name, separated with a period. For example, at, .EDU is the TLD, .SI (for Smithsonian Institution) is the host server, and the “affiliations” portion indicates a subdomain (a computer on the network dedicated to that topic).

The very beginning of the URL (uniform resource locator; an Internet address) even says something about the information you are requesting. For example, the “http://” portion of a URL indicates that you are requesting a Web server that uses HTTP (Hypertext Transfer Protocol). If you typed a URL that started with “ftp://,” then you’d be requesting an FTP (File Transfer Protocol) server. The “www” portion of a URL was initially used to indicate World Wide Web files instead of other types of Internet files, but this portion may not be necessary anymore. In fact, you might be able to locate the site you are looking for without even typing the “www” portion of the URL.

Every part of the domain name indicates where you want to go, what type of data you are requesting, and where you can find the information that you want within the server site. Everything in front of the TLD tells the Internet routers which host computer you want. Information after the TLD tells the host computer where to look within its directories and subdirectories to find the document you’re looking for.

For example, consider this address: This URL tells the “affiliations” computer at the “si” (Smithsonian Institution) to look in its “affiliates” directory and find the “0001.htm” document. The information beyond the TLD isn’t technically part of the domain name, but the host computer relies on it to find the file.

 Names Of Recognition. When you look back at whom to credit with the development of the current system of using domain names, a couple of names stand out. Jon Postel, a computer scientist in charge of administrating the ARPANet, was the first person to handle addressing for the early Internet. In the 1970s and early 1980s, the ARPANet, which was the name of the Internet at the time, was made up of about 235 hosts. It wasn’t difficult to handle the addressing process with that number of hosts.

In 1982, the ARPANet became a TCP/IP network and started using the numeric IP addresses. The ARPANet began to use a naming system and saved all the names to one file called Hosts.txt, which was maintained at the SRI (Stanford Research Institute) NIC (network information center; a body that performs the administrative tasks for a network). The file was updated manually, but it soon became too big to update in this manner as the ARPANet grew. As a result, Postel presented a RFC (Request for Comment) document in 1982 to use the idea of domains and hierarchy.

But it was Paul Mockapetris, a researcher at the ISI (Information Sciences Institute), who actually created the DNS (Domain Name System) the next year. The DNS was more than just a database; it involved additional hardware and software. It was a distributed database, stored on more than one server. It also used a TLD (at the time, it was .ARPA) and was kept up to date. Users didn’t have to remember IP addresses to use the system.

The ARPANet continued to grow even more, and in 1985, the SRI NIC took over the DNS and additional TLDs were made available. Users could register domain names for free. Symbolics registered the first commercial domain name, MITRE registered the first organizational domain name, Carnegie Mellon (, Purdue (, Rice (, and UCLA ( were the first educational domain names.

In 1986, ARPANet had its first dose of real competition. NSF (National Science Foundation) established its own network, NSFNet, which eventually replaced ARPANet. It also created IANA to administer IP addresses. And the NSF and government contractors took care of domain name registration.

Network Solutions, the granddaddy of all registrars, is still a top contender in the business of domain name registrations.
It wasn’t until 1993 that the NSF created the InterNIC (; now a registered service mark of the U.S. Department of Commerce). The InterNIC was developed through the cooperation of several companies (including Network Solutions; to act as the central point of keeping the name registry current and distributing names. This agreement gave the private company, Network Solutions, the ability to register the .COM, .NET, and .ORG domain names through the InterNIC. Registration of domain names also began to cost $35 per year.

 Licensed To Share. When the Internet expanded to include several million registered domain names, the registration process became big business. The idea of placing such power in the hands of a private company was seen as a monopoly. In 1998, the U.S. government decided to distribute the authority by giving other companies the ability to register domain names. ICANN (Internet Corporation for Assigned Names and Numbers), a nonprofit organization, was created to manage how the companies would share name registration. ICANN ( helped create an SRS (shared registration system) and establish policies to resolve problems involving such topics as name disputes and trademarks.

For instance, ICANN’s UDRP (Uniform Domain-Name Dispute-Resolution Policy) made it possible for many decisions about domain name disputes to land in the courtroom. Here, through an agreement or arbitration, name registrars would then fall in line with the decisions.

In 1999, ICANN tested the shared system with five companies, including the America Online service,, France Telecom’s subsidiary Oleane, the Australian Melbourne IT, as well as a nonprofit organization called the CORE (Internet Council of Registrars).

On June 7, 1999, became the next company to register domain names, along with the already established Network Solutions. Currently, the additional companies list has grown to include more than 170 companies that are accredited to register domain names, with approximately 80% of these companies listed as operational. To see a list of registrars, visit the InterNIC site ( All registrars go through a screening process. Once they complete it, ICANN can license them if they pay thousands of dollars in fees.

Apparently, these registrars have plenty of business to go around. According to (, powered by the NetNames Global Domain Name database, there were more than 32 million domain names registered worldwide at the end of 2000. By mid-June 2001, this number surpassed 35.8 million.

How can so many companies register domain names and make sure there are no duplicates? That’s the idea behind the SRS. ICANN wants 170-plus companies to use one shared, central registry. You can register your domain name with any of the licensed registrars, but their costs for registering vary. Also, they may offer different registration services. For example, some will work with your ISP to help you get set up. For more information, see the “More Than Just A Registrar” sidebar.

And if you decide that you are unhappy with one registrar for some reason, you can change registrars after 60 days from the time you initially register.

When you sign up for a domain name, you must provide contact and technical information and submit it to a central registry. You’ll also sign a contract with the registrar and provide the names of your ISP’s primary and secondary servers (unless you don’t have a service provider when you reserve your name). If you don’t have a service provider yet, the registrar will most likely help by parking (reserving) your domain name at its site.

The contact information for your Web site will be published so others can contact you just in case of trademark or technical problems, as well as for consumers’ protection. The information is published on a Whois shared registry service. Most registrars offer this Whois Search option on the home page of their sites. With this search option, you can enter a domain name you want to register to see if it’s already reserved. If it’s available, you can register it yourself.

 More Variety, Please. Of the more than 35.8 million registered domain names on the Internet by mid-June 2001, reports that more than 22.3 million were .COM domain names. With so many businesses vying for the .COM TLD to present their businesses online, this makes it difficult to come up with a memorable domain name. It also has led to a large number of legal disputes over who has the right to what domain name. Some say the answer is to create more TLDs.

In September 2000, ICANN took general suggestions for new TLDs. Not only would applicants come up with the ideas, but they also would be granted the opportunity to manage the new domains. This, along with the required $50,000 application fee, was meant to limit applicants to those with the resources to handle such a proposal.

After reviewing applicants, ICANN met in November 2000 to decide on a list of additional TLDs that were recommended by the Names Council of its Domain Name Supporting Organization. More than 44 companies suggested TLDs that they would maintain. Before the official review, however, the ICANN staff suggested that the group reject TLDs such as .XXX and .KIDS because they might turn out to be problematic. In the end, the ICANN Board of Directors settled on seven new TLDs.

These new TLDs include .AERO from SITA (Societe Internationale de Telecommunications Aeronautiques SC, an airline telecommunications company from Belgium), .BIZ from the JVTeam (a new Internet registrar now known as NeuLevel), .COOP from NCBA (National Cooperative Business Association), .INFO from Afilias (a consortium of 19 Internet registrars), .MUSEUM from MDMA (Museum Domain Management Association), .NAME from the Global Name Registry, and .PRO from RegistryPro (a Dublin company owned by and Virtual Internet). A few of these organizations still need to work out some details with the ICANN Board, but a May 2001 press release from ICANN indicated that the registrars for .BIZ and .INFO were set to begin the registration process this summer.

Another aspect to consider concerns the .US TLD for United States registrants. The Information Sciences Institute of the University of Southern California is in charge of the .US TLD and generally lets state and local governments, as well as local organizations such as libraries, use this TLD. ICANN also is investigating how the .US TLD might be used by businesses and individuals.

In the meantime, some international TLDs are letting individuals and businesses throughout the world use their TLDs via several registrars. You may pay more than $35 per year, but in doing so, you’ll be able to register your domain name with TLDs such as: .TV (Tuvalu), .CC (Cocos Islands), .WS (Samoa), and others. At Network Solutions, it’ll cost anywhere from $50 to $200 a year to register for TLDs such as these .

For the organizations that wish to incorporate foreign language characters into their domain names, Network Solutions also is undergoing a test to allow for multilingual domain names. This possibility would help users who want to use Russian, Japanese, or other foreign language characters that aren’t ordinarily found on typical English keyboards. The test, which is now taking place (and is one of several), includes 350 languages and 39 different writing systems. It costs an introductory price of $25 to $30 per domain name. ICANN plans to watch the progress of such tests and help establish a universal means of handling multilingual domain names.

 Constant Change. Although the system behind domain names has experienced a number of modifications since its conception, one thing remains true: it will continue to change. As the Internet grows and spans the globe, it must adapt to encompass the overwhelming number of new users and their various characteristics and needs. With the current advisory system and the ability for users to voice their views, hopefully these changes will generate better service and a more democratic Internet in the long run.  

by Cindy Krushenisky

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Terms To Know

domain name—The alphanumeric name given to IP addresses so that users can easily remember Web site addresses. For example, smartcomputing .com is the domain name for the Smart Computing Web site. Domain names are separated into several levels of hierarchies, each separated by periods.

host server—On the Internet, a host server is the main contact computer that other computers connect to in order to access information from that network.

ICANN (Internet Corporation for Assigned Names and Numbers)—An organization created by the U.S. Department of Commerce in 1998 to help create an SRS (shared registration system) so that more than one company can register Internet domain names. ICANN also helps to establish domain name rules, especially in areas such as trademark disputes and establishing additional TLDs.

InterNIC—At one time, InterNIC was created by several organizations to handle the domain name registry and distribute domain names. Now that the registry is shared and several companies act as registrars, InterNIC is a trademark of the U.S. Department of Commerce and provides registry information.

IP address (Internet Protocol address)—The numeric address used to locate computers on a TCP/IP (Transmission Control Protocol/Internet Protocol) network. The address includes four groups of numbers (of up to three digits each), with each set separated by periods. For example, is the IP address for the domain name.

SRS (shared registry system)—A system formed after the creation of ICANN. It lets more than one registrar register Internet domain names and prevents the same domain name from being registered to more than one owner. The system, which is currently managed by Network Solutions, began operation in June 1999, after a testing period managed by ICANN.

TLD (top-level domain)—The last characters of a domain name, which are separated from the rest of the name by a period. Popular TLDs in the United States include .COM, .ORG, .NET, or .EDU. Other countries use ccTLDs (country code TLDs) to designate their domain names. For example, Canada’s ccTLD is .CA. Generic TLDs also indicate the type of site it is and where the site is located. For instance, a .COM site is often a commercial business site, and .EDU usually indicates that the site is an educational institution.

Whois—A database that lets users search and locate existing domain names, or check to see if a domain name they want is available. A Whois search tool is available at most domain name registrar sites.

More Than Just A Registrar

With more than 170 currently licensed domain name registrars and competition becoming fiercer among them, each one is trying to set itself apart. Besides presenting customers with the ability to search a Whois database, register for a name, and pay yearly fees, many sites strive to offer something extra.

Some registrars will let you park domain names that you’ve registered for through their service at no additional cost. When you sign up for a domain name, you need to enter a host server and an IP (Internet Protocol) address so the SRS (shared registration service) knows where to look for your Web page. However, if you don’t have a host server for your site yet, you will need somewhere to park the name. Most registrars enter their own host server name and IP address for you until you can set up your own and change it.

Some services, such as Network Solutions (, display a “this site under construction” page for you. Other registrar services let you create your own “under construction” page.

Another feature that many users find is a necessity is the ability to forward users from one domain name to another. For instance, several domain names probably could describe your site. Let’s assume that you decide to register for two or three domain names, but you want visitors of all these domain names to go to the main site you’ve already established (or one that you plan to establish). In this case, you’ll want visitors of secondary domain names to be forwarded to your main domain name. Most registrars offer this service, but it usually requires an additional fee.

At Network Solutions, it costs $50 a year for its “dot com forwarding” feature that provides forwarding services for you from other domain names. Or, dot com forwarding is part of the package when you order a Web address and at least a one-page site from Network Solutions.

Stargate ( offers free URL (uniform resource locator; a Internet address) forwarding as part of its $10 annual fee. At (, URL forwarding or domainname redirection is part of its regular fee ($30 per year).

There are even special services devoted entirely to redirecting people to your Web site from another URL if you take advantage of free Web site hosts on the Internet. They can often redirect e-mail, as well. Popular services include ( and the WebAlias Network ( These services are often free, but they might place banner advertisements on your site and can cause problems with search engines later if you establish a real, registered site.

In addition, registrars help you find all sorts of information about building Web sites, as well as features that will promote your site. It’s likely that you’ll also find a directory of all the domain names the service has registered.

Several registrars assist customers with registering domain names in other countries and reserving domain names with country code extensions.

Network Solutions also lets you set up matching e-mail with your site name and accept secure credit card payments, thanks to its VeriSign parent company.

Registration prices among registrars will vary, but most cost from $30 to $50 a year. Some registrars may ask that you pay the first two years up front, which usually costs from $50 to $80.

To locate a licensed registrar, check with the ICANN Web site ( or visit the InterNIC site ( If you are considering a service that promises to help you register and set up a domain name, but it does not appear on the list, then the service is not a licensed registrar. Several of these services are available on the Internet to help beginners through the registration process and assist them in developing a site for additional fees. Frequently, these are offered by ISPs (Internet service providers) that want to encourage you to use them as your host.

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