The Domain Name System (DNS) is a hierarchical distributed naming system for devices connected to the Internet. Simply put, it allows you to enter a convenient name for your favorite site, e.g. www.ip-info.xyz, and be able to resolve it to its associated IP address. Why would you want to lookup info about a DNS? It could be that you want to know more information about the servers behind a domain name; maybe you need to know the server's IP address or its location or you want to find out information about the registrant.