Domain Name Server

In addition to protocols, communications over the Internet and by electronic mail (e-mail) are governed with Domain Name Servers (DNS). (You will also see DNS sometimes referred to as Domain Name System or Domain Name Service.)The location of a website on the Internet is determined by its Internet Protocol (IP) Address, which is also discussed in Internet Protocol & Their Functions. This is a string of integers divided into four parts by dots with each number ranging from 0 to 255. For example: 139.201.99.2.

This numeric system is how computers understand web addresses. Now imagine if we humans had to memorize or record these numbers to visit the Internet's hundreds of millions of websites. That's why we use alphabetic names for websites-such as www.thatnetwork.com-that are the equivalent of their numeric counterparts. For example, the domain name www.thatnetwork.com has its own numeric IP Address.

This is where DNS comes in. The DNS system is essentially a huge database-undergoing constant change-that's used to map domain names to IP Addresses and IP Addresses to domain names. So when you type www.thatnetwork.com in the Address Bar of your web browser, the DNS system takes this request, recognizes this domain name's numeric IP Address, and then sends the IP Address to your web browser so it will display the web page you requested.

As you can see, navigating the Web without DNS would be difficult indeed.