DDNS
Dynamic DNS is a system that addresses the problem of rapid updates. The term is used in two contexts which, while technically similar, have very different purposes and user populations.
Administrators who maintain the internet, and those who are associated with domains, use devices such as routers, gateways and computer systems using the Internet Protocol Suite, to keep DNS server information up to date. This process is dynamic DNS updating, and is often controlled directly by the domain owner by functionality presented by their registrar. This is the basic updating methodology of the modern DNS system, and has the slow-update problems noted above.
Standard users of the internet who connect to it via an Internet Service Provider (ISP) will be allocated a numeric IP address by the ISP. The address may either be constant ("static"), or may change from one session on the internet to the next ("dynamic"). If it is necessary to be able to access the computer from another location, a numeric address is inconvenient to remember, and an address which changes unpredictably makes connection next to impossible.
For these users there are a number of providers who use the same protocols as administrators to provide a Dynamic DNS service for end users. These are generally implemented in the user's router or computer, which notices changes to its IP address and automatically sends an update message to the DDNS service provider. The communication between the user's computer and the DDNS provider is not standardized, varying from one provider to another, although a few standard web-based methods of updating have emerged over time.
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