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Dynamic DNS (DDNS)

The internet runs on numeric IP addresses. However, do you prefer to remember the domain name google.com or any one of their IP addresses like 72.14.213.106.

DNS (domain naming system) provides the framework to translate domain names to their respective numeric IP addresses. For a domain name to operate in the world-wide public internet, you must first find out if it is already registered by someone else so that you could register it. If it is available, you would need to register it with an registration agent authorised by the world-wide internet authority.

You could either
  • register for a 2nd level domain all by yourself, like blessedgeek.com, or
  • you could share a 2nd level domain so that you allocate among yourselves 3rd level domain names; for example, arumugam.flatistheworld.net, cynthia.flatistheworld.net, abdul-malik.flatistheworld.net, jesus.flatistheworld.net, etc.flatistheworld.net.

DNS can also be used within the confines of a private LAN or WAN, in which case, domain names and IP addresses can be dispensed any how the owners of that private network wish. But, in this discussion, we are concerned about operating within the realm of the public internet.

The need for dynamic DNS service comes about when you wish to serve the public internet from your home and you do not wish to pay the extra monthly fees to get a static IP address for your modem. Not having a static IP address means your modem's IP address is subject to change by your ISP's DHCP servers as discussed in our page on Network Address Translation (NAT).

A DDNS service would allow you use of their DNS service. Every time your ISP's DHCP changes your modem's address, they would update their DNS translation table and push the change to the DNS servers in the rest of the world. In order to monitor the change, a DDNS service provider would require a heartbeat software installed on one of your computers to communicate on regular intervals the current IP address of your modem. Therefore, it would be helpful, as stated in Router, to buy a router where the heartbeat client is built into it.

You could either use
  • your own 2nd level domain name with a DDNS provider, in which case they would probably charge you $30 a month, or
  • use a 3rd level domain name they provide you like 953066-matrix17.kingoflongddnsnames.net; where, even though it's difficult to remember, you would at least have a permanent means by which the world could reach your home-based server.



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