DNS or Domain Name System is defined as the way which domain names on the internet are situated and translated in the IP - Internet Protocol addresses. It maps name used by people to locate a site on IP address which a PC uses in order to locate a site. For instance, if a person types ComputeHost.com in the web browser, server behind will map the name to IP address like 22.214.171.124.
Most of the internet activities, including web browsing relies on Domain Name System in order to instantly provide vital information to connect audience to the remote hosts. The mapping of DNS is distributed on the internet in authority hierarchy. Businesses, access providers, universities and governments, typically have assigned domain name and IP addresses, and run on the DNS servers to handle those names mapping to the addresses. Even, many URLs are even built on domain name.
How DNS work?
The Domain Name System server answer the questions from inside/outside of the domains. The moment server receives request from domain outside regarding name and address of inside domain, it offers authoritative answer. And when server receives request from domain inside, then it passes that request to other server which is managed by its net service provider. In case, server don't know the authoritative source of answer, then it will connect to DNS servers of top-notch domain, for instance - .edu or .com.
How it increases web performance?
In order to promote proficiency, DNS servers can cache answers received by them for a particular time. It permits them to respond instantly next time when a request comes in. For instance, if every employee in a workplace requires an access to a particular training video on the site same day, the DNS server will just have to primarily resolve name, only then it can cater to other requests of cache. The time duration, record time and live time is configurable. Long values minimize load on DNS servers, while short values makes sure most correct responses.