Cloudflare DDNS

This is a small Dynamic DNS (DDNS) script for syncing your public (external) IP address with your Cloudflare DNS.

This was built to be used with my Synology DS918+ to update my DNS record for my Cloudflare zone when my non-static IP address changes at home as I have local services that I like to easily access remotely with a custom hostname.

Installing

Download and setup on your machine.
Install composer dependencies:

$ composer install
Create an API token at Cloudflare or use your global key (security risk!):

The token should have the following permissions (scopes):
- Zones -> DNS -> Edit
- Zones -> Zone -> Read
Copy and edit the example env config file:

$ cp .env.example .env

Setup

Option 1: Synology Module

If you have a Synology server, you can make Cloudflare one of the DDNS service providers and it works just like any other built in one.

Setup a symlink to the script with executable permissions:

$ ln -s /path/to/cloudflare-ddns/script.php /usr/syno/bin/ddns/cloudflare.php
$ chmod +x cloudflare.php

Add the module to the DDNS provider config:

$ cat >> /etc.defaults/ddns_provider.conf << EOF
[Cloudflare]
        modulepath=/usr/syno/bin/ddns/cloudflare.php
        queryurl=https://www.cloudflare.com/
EOF

Next, go to the Synology DiskStation and add the new Cloudflare service provider.
- Control Panel -> External Access -> DDNS -> Add

Option 2: Scheduled Task (cron)

Setup a scheduled task (cron job) as frequently as you want to be checked (daily is common)

echo '0 * * * * root ' >> /etc/crontab

Requirements

Cloudflare account with your email and API key
PHP 8.1 with Composer
Domain name pointed at Cloudflare with the DNS zone activated

dmyers / cloudflare-ddns