Updated: 01/31/2019 by Computer Hope

Short for or Domain Name System, a DNS is a service that receives a request containing a domain name hostname, and responds with the corresponding IP address. The first DNS was designed and implemented by Paul Mockapetris and Jon Postel in 1983.

Tip: DNS uses port 53.

How does it work?

When a user wants to visit Computer Hope, they can type "https://www.computerhope.com" into the address bar of their browser. Once that domain name has been entered, it is looked up on a Domain Name System where it is translated into an IP address that is more easily interpreted by a computer (e.g., Using that IP address, your computer can then locate the Computer Hope web page and forward that information to your browser. Below is a visual example of how DNS works.

How DNS works

As seen above, not every DNS stores every address on the Internet. If a domain name is not found, the server may query other domain servers to obtain its address.

What is the hierarchical structure of DNS

There are millions of websites available on the Internet to make finding an address the domain naming is broken into a hierarchical structure. Below is how DNS is structured on the Internet and an example of three different addresses.


In the above example, all websites are broken into regional sections based on the TLD (top level domain). In the example of http://support.computerhope.com it has a ".com" TLD, with "computerhope" as its second level domain that is local to the .com TLD, and "support" as its subdomain, which is determined by its server.

Related pages

A record, CNAME, Computer acronyms, Database, DNS hijacking, DNS record, Domain, Domain namespace, Hosts file, MX record, Nameserver, Network terms, Port, rDNS, SOA, Web design terms, WINS