Domain Name System (or Service or Server)
is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities.It is most commonly know as an Internet service that translates domain names into IP addresses.
Domain Name System. (2014, December 23). In Wikipedia, The Free Encyclopedia. Retrieved from http://en.wikipedia.org/wiki/Domain_Name_System
DNS Propagation Checker
whatsmydns.net lets you instantly perform a DNS lookup to check a domain names current IP address and DNS record information against multiple name servers located in different parts of the world.
This allows you to check the current state of DNS propagation after having made changes to your domains records.