DNS (Domain Name System), is the service which translates between Internet names and Internet addresses. DNS points a domain name to Server where website data exists. DNS are resolved on IP address of the Server machine. So when a user write domain on browser, then DNS automatically redirects user to server, where website data exists.
The DNS Check in Whoisping.com Tools will check your DNS health and help you find errors, and verify that you domain name has been set up correctly.
The DNS check will automatically find out which DNS servers are used by the domain name you specify, then perform a number of tests on them to make sure that the domain name is properly set up and that those DNS servers are responding in a consistent and correct manner.
When setting up your computer/device to connect to the Internet it is very important that you configure your machine to connect to the correct DNS server. Using the correct DNS server means that you will get the fastest and most reliable lookups for when you're visiting websites online.
While most routers and modems will automatically assign the correct IP address to your computer to use as a DNS server there is some cases in which you may need to configure this manually.
When possible you should try and use the DNS server that is provided by your service provider in order to have the fastest possible DNS lookups.
It is also possible to use Google DNS as your DNS server if you want.