The domain name system is an internet naming scheme. We know it as DNS as well. Computers and other devices use some set of numbers, we know these numbers as IP address. It’s impossible for us to remember all these IP addresses so we use meaningful and often worded labels (called hostnames or if it needs to go online, Uniform Resource Locators, or URLs).
DNS names server has all the record of these names. Name servers are distributed all over the world. There is usually at least one in every domain, organization, company, school, and other major establishments. If you are a subscriber of the Internet service provider (ISP), it’s their service to set up DNS or your connection using their DNS name server. These ISP name servers have catching abilities so they store DNS query results for a certain amount of time. It enables another computer looking for the same URL a faster result.
There are many companies who provide free use of name servers to anyone or any devices that need DNS look ups. To set up these DNS, you just enter the IP address of one or more of these free name servers. Google is also offering these DNS, you just enter the IP address of one or more of these free name servers.