Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Dynamic DNS is a method, protocol, or network service that provides the capability for a networked device, such as a router or computer system using the Internet Protocol Suite, to notify a domain name server to change, in real time (ad-hoc) the active DNS configuration of its configured hostnames, addresses or other information stored in DNS. A popular application of dynamic DNS is to provide a residential user''s Internet gateway that has a variable, often changing, IP address with a well known hostname resolvable by network applications through standard DNS queries.