DNS stands for Domain Name System. DNS is a hierarchical and decentralised naming system for internet resources. In other words, it maintains a directory of domain names along with their associated resources (like IP addresses).
Think of DNS as the internet’s phonebook. When you type a website’s human-readable domain name into the browser’s address bar (e.g., gtmetrix.com), the DNS server translates it into a unique IP address (e.g., 126.96.36.199). This IP address is used by browsers to find internet resources.
A DNS basically translates domain names into a unique IP address.
You can also access the domain by entering the IP address directly into the browser’s address bar. DNS servers eliminate the need for humans to memorise each website’s IP address.
The process of mapping or converting a human-friendly domain name to the appropriate machine-friendly IP address is known as DNS Lookup or DNS Resolution.
The time taken to accomplish this is known as DNS Lookup time, which is represented by the teal-coloured request timing bar on the Waterfall chart.