What is DNS?
2 min read
The Domain Name System (DNS) is the phonebook of the Internet. DNS translates the domain name that you type in the browser (such as
www.example.com) to a computer-friendly IP address (
188.8.131.52), similar to how a phonebook translates a person’s name to a phone number. The IP address identifies the server where the website data is stored, allowing the browser to contact the server and load the page.
Life of a DNS query
The process of translating a domain to an IP address is known as a DNS lookup. DNS lookups are performed by dedicated servers called DNS resolvers. Your Wi-Fi router is typically preconfigured to send DNS queries to the resolver owned by your ISP. However, you can choose to configure your router, operating system, or browser to use a different resolver. Some examples of free, public DNS resolvers include Cloudflare 184.108.40.206, Google 220.127.116.11, and OpenDNS.
As shown in the diagram below, the DNS resolver contacts a series of nameservers (where DNS records are stored) to track down the requested IP address. The resolver analyzes the domain in reverse, starting from the top-level domain (
.com) and ending with the subdomain (
www). The final nameserver in the DNS lookup, called the authoritative nameserver, contains the desired IP address. The concept is similar to how the post office delivers a package — first routing it to the correct country, then to the correct state, city, street and so forth until it arrives at your home address.