For a long time now DynDNS has not been working right for me and it's not as useful and free as it once was.
FreeDNS
Looking for a new service, I found FreeDNS. Their website may not be as polished as the others and it might look a bit scary at first but the service has so far been excellent.
- Go to the homepage and click the "Sign Up" link near the bottom of the screen. Sign up and confirm your email.
- Click the "Subdomains" link at the top left and add one or more subdomains you'd like to use. There are hundreds of domains that you can use but most people prefer one managed by the site's owner, "josh".
- Click the "Dynamic DNS" link at the top left. You can get direct links or scripts to update your IP when it changes.
The direct link is simply an URL with a parameter that, when visited, updates the associated subdomain to the IP of the client that visited it. It looks like this:
"http://freedns.afraid.org/dynamic/update.php?XXXXXXXXXXXXXXXX="
Note that I've replaced the parameter value with XXX to hide it; otherwise, anyone could use it to update the IP address of my subdomain.