Published Jun 19, 2021Updated Oct 26, 2022
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The Domain Name System (DNS) protocol converts domain names to IP addresses. Think of it as a phonebook for the Internet. It’s hard to remember an exact IP address when we want to access a website.

When we request the URL codecademy.com, our computer sends a DNS request to a DNS server. The server then returns the correct IP addresses like to route data to and from Codecademy.

Domain Name

Each domain name is made up of three parts:

third-level-domain . second-level-domain . top-level-domain

  • Top level domain: There are a limited set of top level domains, and many websites use the most common ones like “.com”, “.org”, and “.edu”.
  • Second level domain: The second level domain is unique to the company or organization that registers it, like “codecademy” or “wikipedia”.
  • Third level domain (subdomain): It’s owned by the same group and that URL often directs you to a subset of the website.

For example: shop.codecademy.com (Codecademy’s merch shop):

  • Top level domain: “.com”
  • Second level domain: “codecademy”
  • Third level domain: “shop”

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