I may be totally wrong here, but in the interest of helping, I will give this a try. You wrote:
I went to the web interface to my dynamic dns service, and set a fictitious IP address for my domain name
.....
Any idea what is wrong?
I don't think that this is the way that ddclient is setup to work in a default configuration after installed from synaptic. It is my understanding that ddclient will read the previous ip address information from a file located here - /var/cache/ddclient/
When it runs, it will first determine what the ip address is and then it will compare it with what is in the file located above. If it has changed, then it will connect to the DDNS provider and notify them of the change. Therefore, when it runs it does not contact the DDNS provider unless there is a change. Now, it may do a lookup on the DDNS providers ip lookup page (
example), but determining the ip address is a separate function of updating the dns. Therefore, if you expected it to notice an ip change by entering a fictitious info on the DDNS web interface, I don't think that will work. It might be better to change the ip address information in the cache file and give it a try that way.
I recently installed ddclient and have it running. I tried to start it from a root prompt with "service ddclient restart" and it showed as started. However, it did not do an initial update. It didn't really start updating until I had manually started the service
and running "ddclient" from a terminal prompt. Once I ran, from a terminal, "ddclient", it did a successful initial update and it has been running fine since, although it has only done one ip update since then. What is important here is that the one ipdate that was done, was successfully done after a change in internet service provider. The machine was not rebooted, but once plugged in, it just updated successfully.
I think that if ddclient has successfully updated and is currently running, then it will work fine. Mine starts automatically at boot.
I hope this helps.