Attempted to register, but the verification message does not arrive. I did not see anything resembling it in the mail server logs right after registration, and there is still nothing in the mailbox after 6-7 hours, with a few requests to resend it.
$ nsupdate # or knsupdate
> server update.dynip.dev
> zone YOUR_DOMAIN
> key hmac-md5:key-YOUR_DOMAIN YOUR_BASE64_KEY
> update add YOUR_DOMAIN. 300 IN A YOUR_IP
> send