With xtrose DynDNS you get a simple, free DynDns solution without external providers and hidden costs.
The required online web server can create an infinite number of subdomains for dynamic IP's.
The method used is easy to implement.
For the client servers, the servers that have a dynamic IP, a simple cron job is set up with cron, which sends a simple curl query to the web server at regular intervals.
The web server, which receives the curl request with a PHP script, checks whether the IP of the client server has changed and builds new apache config files.
Another cron job on the web server checks whether there are new apache config files, copies them to the apache config directory and restarts the apache application.
With just a few scripts and a simple setup, you can quickly create your own DynDNS server.