The Domain Name SystemBy Lawrence Abrams on February 19, 2004 | Last Updated: June 18, 2012 | Read 74,593 times.Introduction A key component of the Internet and how it works revolves around the Domain Name System, otherwise known as DNS. The underlying technology behind the Internet, is that when a computer needs to talk to another computer on the Internet, they communicate via the computer's IP Address. The IP Address is a unique set of numbers associated with a particular machine, which will be discussed in a separate article. An example of an IP Address is 216.213.19.27, which is the IP Address that corresponds to www.bleepingcomputer.com. As the predecessor of the Internet, ARPANET, grew larger, connecting to remote machines by their IP Address grew cumbersome. It became more and more difficult for people to remember the IP Addresses associated with the machines they were trying to reach that a system was created to translate easier to remember symbolic names to their equivalent numerical IP Address. Thus the Domain Name System was born. Domain Name System The Domain Name System is the system used on the Internet for the mapping of names, such as www.google.com, to IP Addresses such as 216.239.51.99. Every time a new domain, like bleepingcomputer.com, is registered, that domain is entered into one of the 13 Root Servers spread throughout the world and overseen by an organization called ICANN. Because your domain is in one of these servers, it can be reached and understood by the rest of the users on the Internet. Another key element of the Domain Name System are DNS Servers run by Companies and Internet Service Providers. Every time you connect to a site, you are asking your ISP's DNS Server to resolve, or convert, the hostname such as www.google.com to a an ip address such as 216.239.51.99. If your ISP's name server is not working or can not be reached, then you will not be able to traverse the Internet using hostnames, but instead would have to use their IP Address equivalent. Any time you connect to a site, your ISP DNS Server must find out what name server has the information about the domain for the site you are trying to reach. Your ISP's DNS Server will connect to a Root Server and ask it who the name server is that knows the information about the site you are trying to reach. The Root Server will tell your ISP's DNS Server what server they should next contact for information. Next your ISP's DNS Server will then contact the server that the Root Server told it to contact, where it will be given the IP Address associated with the site you are trying to reach. Real Life Example A lot of what has been discussed may be a bit confusing, so lets do a real life example. In the flowchart below labeled Figure 1, you will see a computer trying to connect to www.google.com and the steps it takes.
We will discuss these steps below:
Conclusion As you can see, the Domain Name System is essential in the use of the Internet. Without it, you would not be able to type in names, but would have to remember the numerical IP Addresses in order to get anywhere on the Internet. If you have any questions about this tutorial, please feel free to talk about it in the discussion forums.
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Lawrence Abrams Bleeping Computer Basic Internet Concepts Series http://www.bleepingcomputer.com Source of Original Content, Tutorials, Help and Computer Basics for the beginning or novice computer user.  When using the Internet most people connect to web sites, ftp servers or other Internet servers by connecting to a domain name, as in www.bleepingcomputer.com. Internet applications, though, do not communicate via domain names, but rather using IP addresses, such as 192.168.1.1. Therefore when you type a domain name in your program that you wish to connect to, your application must first convert ...
 When you use the Internet, you use domain name and hostnames all the time. These hostnames and domain names when put together become the Internet address that you search with. The domain name without a hostname is also the most common email address. This article will explore what hostnames and domain names are and how they are used. We will also discuss TLD's, or Top Level Domains, such as ...
When using the Internet most people connect to web sites, ftp servers or other Internet servers by connecting to a domain name, as in www.bleepingcomputer.com. Internet applications, though, do not communicate via domain names, but rather using IP addresses, such as 192.168.1.1. Therefore when you type a domain name in your program that you wish to connect to, your application must first convert ...
 With so much of Computer use these days revolving around the Internet and communicating with others, its important that you understand what exactly a network is. Without networks, all communication between your computer and other computers whether it be instant messaging, email, web browsing, or downloading music could not be achieved. This tutorial will strive to teach you about networks and ...
 Every machine on the the Internet has a unique number assigned to it, called an IP address. Without a unique IP address on your machine, you will not be able to communicate with other devices, users, and computers on the Internet. You can look at your IP address as if it were a telephone number, each one being unique and used to identify a way to reach you and only you.
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