June 27, 2001

By Karen Kenworthy


I missed you last week!

My Mom and I drove to a small town in southern Oklahoma, to visit William, my Mom's oldest brother. Uncle Bill just celebrated his 82nd birthday, and he's slowed a bit by some recent medical problems. But he's still full of life.

And he's brimming with wonderful stories. I learned about Grandpa Lee, my great-grandfather. And even heard a few stories about Grandpa Noah, my great-great-grandfather! I never knew my ancestors had been such shining lights in the moonshine industry. :)

From The Top Down

Uncle Bill has temporarily satisfied my curiosity about my relatives. But there's still a lot I'd like to learn. To further my quest for knowledge I recently wrote a new Power Tool, one I call Karen's WhoIs. And I can't wait to tell you about it. You'll be amazed what it can uncover ...

But first, let's quickly review the way the Internet's publicly accessible computers and services get their names -- a naming system called the Domain Name System.

Programmers call this system "hierarchical," meaning it consists of several layers or levels. Each level is called a "domain,", which is Internet-speak for a group of computers. Putting this all together, we saw that Internet names look something like this:

Top-Level Domain (TLD)
Second-Level Domain (SLD)
Third-Level Domain (3LD)
... (additional domain levels if needed)
Lowest-Level Domain (LLD)

Hmm... That doesn't look quite right. In reality, domain names aren't stacked one on top of each other. Instead, they are placed side-by-side. The lowest-level domain is listed first, or on the left. And the top-level domain is listed last, at the far right-side of the full name. Each domain is separated from the others by a period.

Putting it all together, a full Internet name looks something like this:


That looks better!

To name your favorite computer or service, start by choosing a Top-Level Domain. Many of the Internet's TLDs, such as "com", are famous. This TLD includes microsoft.com, sony.com, karenware.com, and other captains of industry.

Internet sites belonging to American colleges and universities, such as mit.edu, westminster-mo.edu, and sbu.edu, belong to the "edu" TLD. Other popular Top-Level Domains include "net", "org", "gov" and "mil". Together with the less well-known "int", these make up what Internet folks call the seven generic TLDs or gTLDs.

But there are over 240 other TLDs in use around the Internet. The rest are called country code TLDs (ccTLDs), since each corresponds to one of the two-character codes assigned to the world's countries by the ISO (International Organization for Standardization).

Most Internet veterans have seen several ccTLDs. Among the most popular are "uk" (United Kingdom), "au" (Australia), "fr" (France), "ca" (Canada) and "jp" (Japan). Other ccTLDs are real collector's items, such as "aq" (Antarctica) and "tk" (Tokelau).

Once you've settled on a TLD, it's time to choose a Second-Level Domain name for your computer or service. Here you can be more creative. Unlike your chosen TLD, an SLD can be almost any thing you like.

But there are a few restrictions. First, like all domain names, an SLD cannot contain more than 63 characters. And most importantly, it must be unique, or not already chosen by someone else, within the next higher domain.

Once you've chosen a TLD and an SLD, you can stop. Or not. For example, consider a software company called Microsoft. It has chosen the SLD "microsoft" within the "com" Top-Level Domain. As a result, it can give its computer the Internet name "microsoft.com".

Should they ever grow large enough to own more than one computer, they can tell them apart by assigning third-level domain names to each. For example, if Microsoft were to someday operate a web site, the computer that handles that job might be called www.microsoft.com. A computer that provides support to customers might be named support.microsoft.com.

Who Owns What?

You may not have thought of it before, but every domain, no matter what its level, is controlled by some person or organization. Technically, the entire Internet Domain Name System is controlled by a non-profit corporation called ICANN, the Internet Corporation for Assigned Names and Numbers (http://www.icann.org ).

But ICANN has delegated the control of all TLDs to various organizations. For example, the "net" TLD is controlled by a company called Network Solutions, Inc., in Herndon, Virginia. The same company also controls the "edu", "net" and "org" gTLDs. The "mil" TLD is controlled by the "DoD Network Information Center," an agency of the United States Department of Defense.

Most country-specific TLDs are controlled by a government agency or university. For example, Australia's ccTLD, "au", is controlled by the Australian Research Network, a part of the Computer Science at the University of Melbourne. A non-profit organization called Canadian Internet Registration Authority (CIRA) controls Canada's TLD. And in the Netherlands, control of their "nl" TLD is handled by "Stichting Internet Domeinregistratie Nederland."

ICANN keeps track of which organization controls which TLD in a special database. But what about the millions of SLDs in use around the Internet today? Who makes sure the same SLD isn't assigned twice, within a particular TLD? And who knows the owner of each SLD?

The answer is simple: Each TLD is required to maintain a Registry, or database. For example, want to know who owns microsoft.com? The answer is stored in the Registry of Network Solutions (the company that controls the "com" TLD). Who owns sony.jp? To learn that you'd have to see inside the Registry kept by the Japan Network Information Center, where Second-Level Domains in the "jp" TLD are recorded.

Karen's WhoIs

Now you might think the information stored these Registries would be hard to uncover. But it isn't. Most of the Internet's TLDs allow people to access their Registry via (what else?) the Internet. And ICANN allows us to examine their database of TLD information too.

For example, here's what ICANN's database has to say about China's ccTLD, "cn":

Chinese Academy of Sciences
The Computer Network Center
No.4, South 4th Street, Zhong Guan Cun
Beijing, 100080

Administrative Contact, Technical Contact:
Qian, Hualin (QH3) hlqian@CNNIC.NET.CN
Computer Network Information Center
4 South 4th Street, Zhongguancun
86-010-62569960 (FAX) 86-010-62560928

The "Registrant" is the organization chosen by ICANN to control the "cn" TLD. As you can see, it's the Chinese Academy of Sciences. Their address is shown on the lines that follow the organization's name.

Next, you can see the person chosen by the Chinese Academy all handle administrative and technical inquiries related to the domain -- a person named Haulin Qian. His email address is also shown, followed by his mailing address, phone number and fax number.

Impressed? Let's take a look at the information Network Solutions' has on file for the SLD "whitehouse.gov":

Executive Office of the President (WHITEHOUSE-DOM)
Office of Administration
Washington, DC 20503

Status: Active

Administrative Contact:
Reynolds, William D. (WDR)
(202) 395-6975

Domain servers in listed order:

To save space, I've left out some of the information. But as you can see, the organization that controls the whitehouse.gov SLD is an outfit that calls itself The Executive Office of the President, located in Washington, DC.

If you have a question about the administration of this SLD, you should contact William D. Reynolds at WILLIAM_D._REYNOLDS@OA.EOP.GOV. We also have a mailing address, phone number, and fax number where we can try to contact him.

If you're curious like me, you're wondering "how did Karen come by all this info?" Well, by tradition, the computer where a Registry is stored is called a "WHOIS" server. And programs that access these servers are usually called "whois" too.

Most versions of Unix come with a "whois" program. And many TLDs provide access to their WHOIS server via a web site. But many of us don't have access to a Unix computer. And accessing WHOIS servers via the web can be tedious.

More importantly, both methods require you to know the name of the WHOIS or web server that can provide the information you're seeking. And there are over 250 WHOIS servers around the world, each holding information not available anywhere else. To make matters worse, some queries must be performed in two steps, each involving a different WHOIS server.

For all these reasons, and a few more, I wrote the latest Power Tool program, Karen's WhoIs. It can locate the current information about the owner of any TLD, by querying ICANN's TLD Registry. It can also provide details about the owner of most SLDs around the world.

Best of all, you don't need to know where the information is stored. WhoIs knows the types of information each WhoIs server contains, and directs your request accordingly. If a particular request requires contacting two or more WHOIS servers, that's taken care of automatically too.

What can you do with the new WhoIs program? For starters, you might find out who owns the Internet site that's been sending you all that junk email. Perhaps you're not happy with the service you've received at a commercial web site. Now you can contact the operator of the web site, via email, phone, fax, or regular mail.

In many cases you can discover information about a domain's Internet Service Provider too. A representative of that company will often be listed as the "Technical Contact" in the information provided by WhoIs.

Additional clues to the ISP's identity can be found in the SLD's list of "Name Servers". Called "Domain servers" in the information retrieved by WhoIs, these special computers convert domain names into numeric Internet addresses. And in most cases, at least one name server will be operated by their ISP or another company with a special relationship to the SLD.

For example, whitehouse.gov's Name Servers are all in the GTEI.NET Second- Level Domain. A quick check, using Karen's WhoIs, reveals that GTEI.NET is actually BBN Corporation, a company located in Cambridge, Massachusetts, and a pioneer in providing Internet connections and services.

There's a lot more to say about WhoIs, but it will have to wait until the next time we get together. In the meantime, if you'd like to start your behind-the-scenes exploration of the Internet today, download Karen's WhoIs from its home page at:


As always, both the program and its Visual Basic source code are free.

And don't forget to visit my home on the web at:


There you'll find all my other free Power Tools, back issues of our newsletter, and soon, news about my new Power Tools CD!

And if you see me, my Uncle Bill, or even Haulin Qian, on the 'net this week, be sure to wave and say "Hi!"

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