What is DNS?
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 (93.184.216.34), 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.
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 1.1.1.1, Google 8.8.8.8, 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.
flowchart LR
accTitle: DNS lookup process
A[Browser] -- What is the IP address of www.example.com? --> B((DNS resolver)) -- Where is .com? --> C[("Root nameserver")]
C --IP of .com nameserver--> B
B -- Where is example.com?--> D[(.com nameserver)]
D -- IP of example.com nameserver --> B
B -- Where is www.example.com? --> E[(example.com nameserver)]
E -- 93.184.216.34 --> B
B -- 93.184.216.34 --> A
For more background information on DNS, refer to our Learning Center ↗.