A Domain Name Server is a server computer on the World Wide Web that allows us
to locate other computers on the World Wide Web using a virtual domain name (e.g. yahoo.com).
The role of DNS servers is to map easy-to-remember domain names to the
physical location of another computer where the website is hosted. The
nodes (i.e. computers) on
the Internet are identified by an IP address (e.g. 213.2.1.23).
The mappings are replicated on many domain name servers around the
world. Consequently, it can take 24 hours or more for a new or changed
domain name to propagate to all DNS servers world-wide.
