Dynamic dns server update

I have created a remote TCP/IP COM port where I use HyperTerminal to make a TCP/IP connection to a remote terminal. I am using an unrestricted APN sim to connect to the internet, so I get a real dynamic IP when I connect. I then type the IP address and port into HyperTerminal and connect.

This all works perfectly. What I now need to do is create a DYNAMIC DNS update service where I connect to dynupdate.no-ip.com:80 and update my local IP onto the server. I will then be able to use a URL to connect to the remote terminal instead of typing in a new ip every time the module connects.

Does any one know how to acchieve this?

The documentation for your chosen D-DNS service will tell you…

However, this relies upon your device having a Public IP address…