How to forward Domain Name to Virtual IP ?

I’ve a data-logger module that connect to internet, the ip is dymanic, always changing, thus I configure the modem there on DynDNs for updating me always with the latest IP. The problem that my program which connect to that logger connecting via IP only – not domain name, so every time I resolve the new DynDns , then re-configuring the IP setting in my program! I read that you can configure a Virtual IP like failover cases, how we can round that? Server is Win 2003