CPS100 • Introduction to Computers


Lakeland College • Japan Campus

Domain Geography

So now, hopefully, you have a slightly better idea of what the Internet is, where you are located on the Internet, and how you are connected.

The next question is, how are those connections made? How do computers make connections?

Domains

Now we come to domains. What is a domain? Put simply, a domain is an address on the Internet which is maintained by various servers (e.g., email servers, web servers, etc.). We usually think of a domain as containing a "web site," but domains can contain much more than just that.

Each domain can have an IP Address. To connect to the domain, we type in its address, and our computer seeks that somain and makes contact.

There is a problem, however. These IP addresses are much too difficult to remember. Seriously, could you imagine someone saying, "Check out my web site at 2001:0db8:85a3:08d3:1319:8a2e:0370:7334!" Me neither.

As a result, we needed a better way to express an address on the Internet. What was created is called the Domain Name. You know these—it's domain.com. That's a domain name, like cnn.com, wikipedia.org, or lcjapan.com.

Each domain name is connected to an IP address. In a way, they are the same thing; you can type an IP address directly into a browser. Go ahead, try this address: http://119.245.180.222. That will take you to LCJ's home page. Another way to get to the exact same page is to go to http://www.japan.lakeland.edu. So:

japan.lakeland.edu = 119.245.180.222

Think of it in the same way as you think about a phone number. If you want to call somebody, you tap out their telephone number. However, if your cell phone is smart enough, you would simply look up their name, and the phone would automatically find the right number and connect you.


A Few Other IP - Domains:
http://151.101.100.73
http://216.58.197.206
http://54.240.250.0
http://54.239.26.173
http://198.105.197.36

That's what browsers do: when you type in a domain name, they look up the IP address for that domain name and they take you to it. This is done by the Domain Name System (DNS).


A domain name has several parts:

http:// www. cps100. lcjapan .com
HTTP protocol web server subdomain domain name top level domain
  • HTTP protocol: states that the transaction uses the HTTP protocol
  • web server: defines the web server (not the mail server or FTP server)
  • subdomain: a subdomain is a directory set aside to be a special part of the domain, instead of being a directory within a domain (such as http://www.lcjapan.com/cps100/)
  • domain name: the name of the domain being used
  • top level domain: the category of domain being used

Most people are used to typing the letters "www" before a domain name, as in "www.lcjapan.com". That "www" refers to the part of the domain "lcjapan.com" which is reserved for the web site—the web server. There may bo other servers on the domain used for email and other network connections, using various protocols:

www.lcjapan.com
web site
ftp.lcjapan.com
file transfer point
pop.lcjapan.com
incoming email
smtp.lcjapan.com
outgoing email

Top-level Domains (TLDs)

Top-level domains usually note which category a site belongs to. For example, a .com site is supposed to be commercial; a .org site should be an organization, usually not-for-profit. There is no rule that says a site must follow the rules for .com or .org, but it is expected that top-level domain names will be chosen to match the nature of the site.

Top-level domains come in various types, but the main ones are .com, .net, and .org for private web sites, and .gov, .edu, and .mil for government, educational, and military web sites. Some TLDs, like .gov, .mil, and .edu are reserved for special use and are only given to people or organizations that meet the requirements. For example, .edu is given only to accredited educational institutions, and only one domain name is allowed per school.

These are just a few of the many TLDs, however; there are many more:

.com
commercial
.net
network entity
.org
organizations
.biz
business
.name
name (personal)
.mobi
mobile (cell phone-specific)
.info
information
.gov
U.S. government only
.mil
U.S. military only
.edu
accredited educational only
.aero
air-transport industry only
.travel
travel-related entities only

There are more, and new ones are created from time to time. Top-level domains proposed but not yet official: .eco (environmental organizations), .mail (for email, as a way of cutting off spam), .geo (for geographical locations), and others.

National Domains

Each country has a domain, which it controls. Some examples:

.ca
Canada
.cl
Chile
.cn
China
.es
Spain
.fr
France
.jp
Japan
.lk
Sri Lanka
.uk
United Kingdom
.us
United States
.zw
Zimbabwe

These are usually used with 2-letter versions of the common suffixes, such as ".co.jp", ".ne.es", and ".or.zw".

Each country controls the use of its suffix, and can charge whatever amount of money that it likes. The ".jp" suffix is sometimes pretty expensive.

One country became rich because of this naming system. The tiny country of Tuvalu did not get ".tu" because Tunisia is before it, alphabetically. So Tuvalu got ".tv". However, there are rumors that when Tuvalu eventually disappears because of global warming, the ".tv" domain suffix will also disappear.

Recently, the fact that countries control domains has hit the news. There are services which create mini-URLs, to replace longer URLs which will not fit in Twitter or other short message spaces. The most famous is called bit.ly, and an example address is one I have created for this web page: http://bit.ly/QC0eHM. Click on that, and it will expand to "http://www.lcjapan.com/in/in02.php" and take you to this web page.

The problem? Well, these shortening services decided to end with the "ly" domain, as a cute, short, and easy-to-remember suffix. But the "ly" domain is owned by Libya, not recognized as a liberal, free-wheeling place. Libya has "morality laws," and a web site with the domain "vb.ly" was seized and taken down by the Libyan government for "promoting illegal activities"—namely, shortening URLs to pornography sites.


So, we have defined a domain as being a location on the Internet equal to an IP address, allowing you to make contact with a collection of servers which host a web site. Although I have explained the various parts of domain names, from now on, I will refer to the whole addresses as "domains."


Terms to Know

domainan address on the Internet which is maintained by various servers
DNSDomain Name System, a system which translates domain names into IP addresses
subdomaina special directory in a domain; instead of being added as a directory (lcjapan.com/cps100/) it is added directly into the main domain name (cps100.lcjapan.com)
top level domainalso called a TLD, these are the extensions added to the end of a domain name; they serve to categorize the web site (commercial, network, organization, education, government, etc.)

Previous Chapter Chapter Quiz Next Chapter