DDNS or DynDNS can be understood as a DNS (Domain Name System) extension. The DNS is a global directory system that knows the IP address for each registered domain to allow access to websites, e-mails, or FTP. The process works like telephone directory assistance, where current contact information is kept and issued on request. The DNS 'searches' for the IP address that belongs to the hostname (if it can’t be found in the DNS cache) and is in constant exchange with the corresponding internet service provider’s DNS database. In the best case, the request is answered with the matching IP address. IP addresses can also be translated into the respective domain names in the opposite direction. However, this is more difficult, since reverse DNS is not an internet standard requirement, and the DNS is not optimized for it.
The DDNS service procedure supports the assignment of dynamic IP addresses to a particular domain. A comparison with the internet provider’s DNS databases takes place automatically. The DynDNS automatically ensures that changes to the IP address are detected and DNS entries are updated accordingly. To connect to your computer, you only need the domain address registered in the DDNS service.