Fastmail now supports Dynamic DNS for domains whose DNS we host.
It speaks dyndns2 for many routers and ddclient, plus a one-line API for your crontab. Tokens only write to records you've opted in to, never A/AAAA, MX or DKIM.
For some, this blocked hosting DNS with us. Remove it, and we can handle MX, SPF and DKIM. The post walks through exactly how it works.
It's opt-in. Nothing changes unless you set it up.
https://www.fastmail.com/blog/keep-your-home-server-reachable-with-dynamic-dns/
