First install afraid-dyndns with the command:
sudo yum install afraid-dyndns
Now open the configuration file /etc/afraid-dyndns.cfg and we need to change the following:
Notify = root@localhost # leave empty to suppress notifications
CacheFile = /var/cache/afraid-dyndns/IP
AccountHash = <value>
The number above that you see in the actual URL is the account hash that you need to configure in the config file. Though it is very simple but could never get this correctly 🙂 until today.