elescondite

dtdns.com is still free

An even simpler option, and one that follows your IP address changes is to add a CNAME record. What this does is create a pretty name (an alias really) that points to your ugly name at dyndns.org. This way, DynDNS handles keeping your IP up to date, and the alias just follows along. I don't know what system your DNS is on, but the resulting record should look like: cctv.mywwebsite.com. CNAME IN 600 cctv.dydns.org. The "600" tells DNS servers to cache this entry for a maximum of 600 seconds, or 5 minutes.