A PHP script that checks for changes to your public IP and updates a Cloudflare "A" record with your new IP address when it detects a change.
You should have Composer installed.
composer install
Create an API token: https://dash.cloudflare.com/profile/api-tokens
Create an API token with permissions to edit DNS records for the zone you wish to use.
cp config.template.php config.php
Add your TOKEN value and add SMTP info, if you want to enable email notifications about IP changes.
php cli.php
Run the script yourself from the command line the first time. You will be prompted to define the zone name and record name. The script will obtain your current public IP and get the zone and record IDs. If a record does not exist with the name you provided, one will be created.
Each time script runs again, it will obtain your current public IP and compare it with the last value saved in the JSON file. If it detects a change, it will update the DNS record.
Add the script to a cron job to automatically check for IP changes at a given interval.
Edit cron jobs for current user: crontab -e
or for a specific user sudo crontab -u user -e
Paste and edit the line below to suit your needs. This runs the script every hour and stores the output in the log file in the same directory.
0 */1 * * * /usr/bin/php -f /path/to/Cloudflare-Dynamic-DNS/cli.php > /path/to/Cloudflare-Dynamic-DNS/log