Now that Oracle is rumored to be taking over Dyn, this should be the last signal you need: Dyn is nothing like the cute little company called DynDNS that we liked so much in the 90s of the last century. Remember talking on IRC when someone gives you an address for an FTP hosted via their 28.8k modem on flyingdickweasels.dyndns.org? No? Damn. You’re younger than I am. Enjoy that youth, it won’t last!
Dyn has become more and more corporate over the years and isn’t cool anymore. But you know who’s a cool and offers free dynamic DNS? Afraid.org/FreeDNS. It used to be that afraid.org’s dynamic DNS mode isn’t directly supported in home router firmware or NAS devices, but that’s changed. Even Synology NAS now support it easily. If your router doesn’t have support for it, you can get it to work on anything that can run shell scripts, Windows batch scripts or PowerShell. Instructions are included when you set up your domain.
They also support the nice trick of using your own custom domain and dynamically updating its subdomains, but you’ll have to pay US$ 30/year for a pro account if you need that. If you just want to use their top-level domains and don’t need your own, that’s still free and has been for over a decade. They own chickenkiller.com, for example. You can work with that, can’t you?
Full disclosure: I’m not paid anything for this. I’ve just been a happy afraid.org customer for more than 10 years now without a single issue, and I laugh in the face of Dyn, whose slide into zombie corporate culture couldn’t meet a more fitting end than being absorbed by the ultimate peddler in corporate zombieism: Oracle.