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Comment by jve | Hacker News Reader

I'd also like to learn more about about this subject. Cloudflare offers some API to update DNS: https://developers.cloudflare.com/dns/manage-dns-records/how...

I'd like to see some of those scripts that use CF API to detect and update IP in dynamics public IP environment.

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It’s not particularly pretty, but here is my home-grown script for doing exactly that. It coordinates between Cloudflare DNS, my Unifi Security Gateway, and haproxy running on my home servers to keep my IPv4 and IPv6 addresses up to date everywhere.

https://gist.github.com/thedanbob/df4cc49aa3e60581e010f443ac...

I used to use Cloudflare's API to do this, but then we changed ISPs and now are behind CGNAT, so we don't even have a public IP. To publicly expose my web server, I created a Cloudflared tunnel, and have our DNS (which is also hosted at Cloudfare) point to the tunnel. It works quite well, and adds some security because we're no longer visible to attackers using IP address scans.

If you have a server with a public address, a machine with a private address can simply use e.g. curl to access some (even non-existant) url on the server periodically which can then be extracted from the logs by a script on the server.

I actually use this to announce my internal address, even without a web server, just by accessing a locked port on the server, where the firewall logs this access.

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