This is how to setup Endian firewall and dynamic DNS at freedns.afraid.org. This should also work in IPCop but I have not tested.
=== In freedns.afraid.org ===
* go to Dynamic DNS and click on Direct URL, you will get a URL like this: http://freedns.afraid.org/dynamic/update.php?UlFMaEtpexxxxxxxxxxxxxxxVHE6MzkxNDQ1NA==
* copy the part after the ? mark, e.g. “UlFMaEtpexxxxxxxxxxxxxxxVHE6MzkxNDQ1NA==”. This is your secret key.
=== In Endian Firewall ===
* go to Service > Dynamic DNS.
* Choose freedns-afraid.org as the service
* fill in your secret key (copied above) to the Username field
* leave the password field blank
* the hostname and domain name fields are optional
* click Add and Force Update
* go to Logs > System Logs
* you should see “Dynamic DNS afraid.org : success”