Editing Dynamic DNS (section)

== Background ==
In the initial stages of the Internet (ARPANET), addressing of hosts on the network was achieved by static translation tables that mapped hostnames to [[IP address]]es. The tables were maintained manually in form of the [[host file]]. The [[Domain Name System]] brought a method of distributing the same address information automatically online through recursive queries to remote databases configured for each network, or [[Domain name|domain]]. Even this DNS facility still used static lookup tables at each participating node. IP addresses, once assigned to a particular host, rarely changed and the mechanism was initially sufficient. However, the rapid growth of the Internet and the proliferation of personal computers in the workplace and in homes created the substantial burden for administrators of keeping track of assigned IP addresses and managing their [[address space]]. The [[Dynamic Host Configuration Protocol]] (DHCP) allowed enterprises and [[Internet service provider]]s (ISPs) to assign addresses to computers automatically as they powered up. In addition, this helped conserve the address space available, since not all devices might be actively used at all times and addresses could be assigned as needed. This feature required that DNS servers be kept current automatically as well. The first implementations of ''DDNS'' fulfilled this purpose: Host computers gained the feature to notify their respective DNS server of the address they had received from a DHCP server or through self-configuration. This protocol-based DNS update method was documented and standardized in IETF publication in 1997{{Ref RFC|2136}} and has become a standard part of the DNS protocol (see also [[nsupdate]] program).

The explosive growth and proliferation of the Internet into homes brought a growing [[IPv4 address exhaustion|shortage of available IP addresses]]. DHCP became an important tool for ISPs as well to manage their address spaces for connecting home and small-business end-users with a single IP address each by implementing [[network address translation]] (NAT) at the customer-premises router. The [[private network]] behind these routers uses address space set aside for these purposes,{{Ref RFC|1918}} masqueraded by the NAT device. This, however, broke the [[end-to-end principle]] of Internet architecture and methods were required to allow private networks, with frequently changing external IP addresses, to discover their public address and insert it into the Domain Name System in order to participate in Internet communications properly. Today, numerous providers, called ''Dynamic DNS service providers'', offer such technology and services on the Internet.

=== Domain Name System ===
DNS is based on a [[distributed database]] that takes some time to update globally. When DNS was first introduced, the database was small and could be easily maintained by hand. As the system grew this task became difficult for any one site to handle, and a new management structure was introduced to spread out the updates among many [[domain name registrar]]s. Registrars today offer end-user updating to their account information, typically using a web-based form, and the registrar then pushes out update information to other DNS servers.

Due to the distributed nature of the domain name systems and its registrars, updates to the global DNS may take hours to distribute. Thus DNS is only suitable for services that do not change their IP address very often, as is the case for most large services like Wikipedia. Smaller services, however, are generally much more likely to move from host to host over shorter periods of time. Servers being run on certain types of [[Internet service provider]], [[cable modem]]s in particular, are likely to change their IP address over very short periods of time, on the order of days or hours. DDNS is a system that addresses the problem of rapid updates.