Dynamic IP for subdomain

[browngb]

I have an ISPConfig 3 server on a VPS at TekTonic. I have a dynamic IP at my house that I would like to point a subdomain of my VPS to, such as athome.mydomain.com.

Is there some way that I can script an A record change for a particular domain? Something like:
My home server visits a page on my VPS>Script on VPS tells ISPConfig IP visit came from>ISPConfig changes record of subdomain to that IP.

Thanks.

[cfoe]

do not make it harder on you as it should be.

Use dyndns.com or another dynamic dns service. It's free.
To use a custom domain name just use a CNAME entry to make an alias for the domain you get from the dynamic dns service