How works Domain Name Server

A Domain Name Server is one of the pillars of the Internet because it has the ability to resolve URI addresses in IP addresses valid for the computer, this technology was invented to be much easier to remember a domain name than a set of numbers.

How works DNS

When it’s write the name of a domain in the address bar of a browser, it makes a request to the 1st DNS to resolve the domain and return the corresponding IP address, if this 1st DNS can not resolve the domain name, it will send a request to another DNS server that will attempt to resolve the domain name, if it manages to resolve the domain, it will send the request to the 1st DNS to update its domain list and then it will return the request to the device that sent the request. This device will update its list of domains and will give the answer to the browser that will be in charge of looking for the page that we have requested through the IP obtained from the DNS.

If none of the DNS can not resolve the IP address, then a server not found error will be shown on the browser. The DNS use the UDP protocol on port 53, if the DNS exceeds the limit for the response it is possible that the DNS uses the TCP protocol on port 53 to guarantee delivery.