"Just for info, maybe everybody knows that, just in case someone is wondering how to update a custom domain on dyndns.org, edit /sbin/e-smith/dynamic-dns/dyndns.org and replace system=dyndns by system=custom in the command to update your host.
If you do not do that you have a nohost comment in the log file (/tmp/dyndns.log) and dyndns think you're upating a dyndns record instead of a custom record"