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Cloudflare DDNS curl scripts that call CF-API (v4) directly.

My third-party DDNS service stopped working recently with CF. It seems CF has moved to a new API (v4).

The very good news is you can ditch third-party DDNS and simply run a DDNS shell script as a cron job every minute on your webserver. It calls the new CF API directly.

This is a bare bones script that requires:

• Internet connectivity is available.
• CF API v4 service is available
• api.ipify.org service is available

You need the Zone ID, Authorization key and A-record ID for your domain.

Fetch the first two from your CF account.

Create the A-record in CF named "dynamic".

Create the CNAME alias (example.com --> dynamic.example.com)

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Fetch The A-record ID with cloudflare-dns-id.sh

Run cloudflare-ddns.sh as a cron job * * * * * /.../cloudflare-ddns.sh

Test by changing your A-record to a bogus IP and then deleting /tmp/ip-record The cron job will change the A-record to your webserver IP address on it's next run.

Marvel at your own dynamic dns service - no more surrendering your CF Authorization key to a third party DDNS service.

Note that the CNAME alias masks your real IP address - a fundamental advantage of CF. Naming the A-record directly as your domain (example.com) would allow anyone to see your real IP address just by ping example.com. Try it!

Note that you will need to update this script:

• if your CF Zone ID, Authorization key, or A-record ID change. Only you can change these.
• if CF API v4 is deprecated. It is currently new, so should be stable for many years.
• if api.ipify.org is deprecated. There are many others. Or use dig if you like.

TO DO

• Convert curl from linux bash script to other platforms.
• DONE: Windows BAT

DO NOT commit your Authorization key to GitHub - thar be dragons. Purge any such commits and change your key.

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