How the DNS System Works

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Finding a Web Address on the Internet – How the DNS System Works

The Domain Name System (DNS) is how the name of a website you’re seeking is matched to its IP address.

Why use DNS?

Anything connected to the Internet has an IP address, whether it’s a website, computer, laptop, smartphone or tablet. They are a series of four numbers ranging from 0 to 255 with each separated by a period (example:

It’s possible to navigate to a website by typing in its IP address, but it’s much easier to remember its domain name, which is the name of the website that ends in an extension such as .com or .org (example:

Another reason using a domain name system is practical is sometimes websites’ IP addresses change, and some sites use multiple IP addresses.

How it works

The process by which you connect to a website through a DNS server, and that server resolves domain names to IP addresses is called DNS name resolution. It takes place in eight steps:

  1. You type a domain name into your browser.
  2. Your browser sends a query seeking the corresponding IP address of the domain name you’ve entered.
  3. The query goes to the recursive resolver, a server which is usually operated by your Internet Service Provider or wireless carrier. The recursive resolver will take your query to other DNS servers in order to resolve it.
  4. The first kind of DNS server it asks is called a root server. Root servers, which are set up in all corners of the world, know DNS information about top level domains, which is the extension at the end of the domain name (example: .com)
  5. From there, the query goes to a top level domain (TLD) server. TLD servers store the address information for second level domains, which is the first part of the domain name (Example: examplewebsitename) from the top level domain (.com). When the query reaches the TLD server, the server gives the IP address of the domain’s name server
  6. The recursive resolver then sends the query to the name server, which knows the IP address of the full domain name entered, and it sends this information to the recursive resolver.
  7. Once the recursive resolver learns the IP address for the domain name in the query, it reveals it to your browser.
  8. In the final step of the process, your browser sends a request to the website to access its content with the IP address it now knows.