DHCP.io - Free Dynamic DNS
DHCP.io allows you to control DNS entries beneath the .dhcp.io domain.
You can quickly and easily configure a name such as gateway.dhcp.io to point to the IP of your home gateway - with both IPv4 and IPv6 supported.
Once you've registered you can update your name(s) via a simple call to curl, or using your web-browser, with no need to install or configure any client.
Unfortunately registration is closed to new users.
Git-based DNS Hosting
If you find this service useful you might wish to look at our sister-site, which allows publishing DNS records directly from a git repository:
It uses the same distributed and redundant backends, and allows you to update your records whenever you like, with fixed pricing based on the number of zones you host.
Thanks to the use of git revision control system you maintain a complete history of your changes.