DDNS stands for dynamic DNS, or more specifically, dynamic Domain Name System. It's a service that maps internet domain names to IP addresses. It's a DDNS service that lets you access your home computer from anywhere in the world. DDNS serves a similar purpose to the internet's Domain Name System (DNS) in that DDNS lets anyone hosting a web or FTP server advertise a public name to prospective users.However, unlike DNS which only works with static IP addresses, DDNS is designed to also support dynamic (changing) IP addresses
Dynamic DNS (DDNS)
For example, if you have FTP software on your computer to turn that device into an FTP server, you'd install the DDNS application on that computer. That computer is the one that users will reach when they request your server, so it's the one that needs to always be updating the DDNS provider with its current IP address. What the software does is monitors the dynamic IP address for changes. When the address changes (which it eventually will, by definition), the software contacts the DDNS service to update your account with the new IP address.
A DDNS service is really only part of the equation when serving files through the internet from your computer. You also need to tell your router which computer on the network should be contacted when a user outside of the network tries to access the server. This is done through port forwarding on the router.
Several online providers offer free DDNS subscription services that support Windows, Mac, or Linux computers. A few of our favorites include NoIP, FreeDNS, and Dynu. Something you should know about free DDNS services is that you can't just choose any URL and expect to have it forwarded to your server. For instance, you can't pick files.google.org as your file server address. Instead, after choosing a hostname, you're given a limited selection of domains to choose from.
Tip : Here are some example situations for when you might need a static IP address:
1.Setting up a home file server
2.Adding a second router to a network
3.Enabling access to a computer when away from home/work
4.Forwarding ports to certain devices
5.Sharing a printer over a network
6.Connecting to an IP camera when away from home
Open a web browser and go to: http://192.168.1.1/
Then, log in to the router's administrator console and access its configuration screens.
The procedure may fail for the following reasons:
The router has failed and is unresponsive to connections through the browser.
The router is set up to use a different address and not 192.168.1.1.
The computer and the router need to be on the same network to access it at this local address.