Understanding Levels in Domain Name System

A Web Hosting Article Contributed by Raj Rao

What is a Domain Name System?

Domain Name System is a system that correlates a Domain Name with a physical network address of the Internet resource. All the Internet resources, like Servers and Websites have a unique network address called the Internet Protocol (or IP) address. This address consists of 4 sets of 3 digit numbers like 202 42 142 249 in the range of 0 to 255. It is very hard to remember these numbers to access the specific website.

Hence, the Domain Name System was created to provide a unique yet memorable name for each of these network addresses. So, if you create a website with a network address of 223 34 54, you can register a domain name like 'my-company.com' and assign the domain name to this network address. Anybody who can remember the name 'my-company.com' will be able to reach you through the Internet.

What are the Levels in Domain Name System?

A Domain Name consists of two parts: the name, followed by a dot and a suffix. Example: mycompany.com or mycompany.net. The suffix after the dot is called the Top Level Domain (COM). The name is called the Second Level Domain (mycompany). Yes, you need to read from the right to left in a Domain Name! What is not known to many Internet users is that there is a hidden dot 'after' the COM. Example mycompany(.)com(.) So, you are actually counting the dots when you count the levels.

In fact, you can create additional levels by adding a dot 'before' the name (mycompany) and putting another name before that dot. Example: mail.mycompany.com(.). In this case, 'mail' becomes the Third Level Domain.

How Can I Create and Use Sub-Level Domains Within My Domain Name?

You can use the sub-level within your registered Domain Name very creatively. And best part is all domains created within a sub-level of your domain name is free! They are called sub-domains). However, your hosting service provider may charge a small fee for setting up the DNS records for the sub-domain (This should not be more than $2 per sub-domain).

Lets take some scenarios: You own a large chain of shops spread across several states. You need a way to let each shop (in different states) to have its own website. You can create one domain name like myshop.com and then add additional sub-domains like IA MYSHOP COM, MI MYSHOP COM, NY MYSHOP COM etc for each shop. Each of these domains can be connected to a single website or different websites, even on different servers located anywhere in the world!

Another good use of sub-domains is to use it for internal services like mail, files storage, databases, administration etc.

To summarize:

a) Register a Second Level domain name with any Domain Name Service Provider;

b) Connect the Domain Name to a website;

c) Request your WebHosting service provider to create additional sub-domains in the Domain Name System (DNS);

d) Connect each of these sub-domains to a different website or a service.