Internet Video Series, Part 2


Episode 17, Segment 04 of 07

Understanding Dynamic DNS

If you don't know what the - "Domain Name System" - ( DNS ) - is, you should watch the movie entitled - "Configuring Your Internet Connection Part 1: The Dynamic Host Control Protocol" - before proceeding, because those concepts are explained there, and - this - movie builds on them.

If you've seen that movie, then you should be fairly comfortable with IP addresses in all of their popular forms, including - "Domain Name" - addresses and with the way those Domain Name addresses are translated into the 32-bit binary numbers that your computer hardware understands.

Conventional Domain Name Servers don't update their databases until they are told to do so. Because most IP addresses don't change very often, the usual expectation is that DNS servers will retain information about your IP address for at least several weeks. Those DNS servers talk with each other all of the time, exchanging information about Domain Name Addresses as necessary to make the information available to the entire world. There are thousands and thousands of Domain Name Servers on the Internet, and each is responsible for some small proportion of the computers constituting cyberspace. It usually takes about 24 hours for a Domain Name change to be propagated to all of those servers.

Because your public IP address may change at any moment, you will need faster service than that. Fortunately, several enterprising companies have developed a clever technique that can keep up with changed IP addresses within a few minutes. That technique has come to be known as - "Dynamic DNS", and it involves both - client - and - server - components.

The Dynamic DNS - servers - are managed by various popular service providers on the Internet, and they automate all of the complex work for you. Those servers associate you with some constant Domain Name address, and they are constantly listening for messages from you, by which they can learn about any changes to the numeric IP address that your ISP has assigned. Whenever they are informed that your public, numeric IP address has changed, they quickly update their Domain Name database, and they constantly inform all of the other DNS servers on the Internet that authoritative information about your Domain name address must be obtained directly from them, and must be refreshed if needed again, even if only a few minutes later. As a result of this arrangement, everybody can always find your services by referencing your Domain Name.

All of the most popular Dynamic DNS Service providers offer various levels of service, including some free options.

Episode 17, Segment 05 of  07