What exactly does DynamicDNS do?
Functionally, it makes your dynamic IP address static. While your ISP will continue to assign you dynamically-changing IP addresses, DynamicDNS will consistently point a designated third-level domain (host) name to your dynamically-changing IP addresses. For example, you can designate home.mydomain.com to always point to your home computer even though your ISP regularly changes its IP address.