Cloudflare DDNS for UniFi OS

A Cloudflare Worker script that exposes a UniFi-compatible DDNS API to dynamically update the IP address of a DNS A record.

Why?

I have a UniFi Dream Machine Pro (UDM-Pro), and I want to update my Cloudflare domain name DNS records when my public IP address changes. Unfortunately, UniFi does not come pre-configured to support Cloudflare as one of its DDNS providers.

Configuring Cloudflare

1. Create a new Cloudflare Worker
2. 'Quick Edit' the worker within your browser.
3. Copy and paste the contents of index.js into the code editor for your worker. Ensure that you are replacing any boilerplate/code that is currently there.
4. Once you have created the worker, take note of it's *.workers.dev route. More on routes for Cloudflare Workers here.
5. Create an API token so the Worker can update your DNS records. Go to https://dash.cloudflare.com/profile/api-tokens and select "Create custom token". Enable permissions for both Zone:Read and DNS:Edit. Copy your API Key - you will need it later when configuring your UniFi OS Controller.
6. Update the 'KEYS' map at the top of the worker javascript code. Each key must be exactly 8 characters, and the value should be the allowed hostname value for that key. You will prepend the 8-character key to the password (token) in the configuration below.

Configuring UniFi OS

1. Log on to your UniFi OS Controller
2. Navigate to Settings > Internet > WAN and scroll down to Dynamic DNS.
3. Click Create New Dynamic DNS and enter the following information:

• Service: choose dyndns
• Hostname: the full subdomain and hostname of the record you want to update (e.g. subdomain.mydomain.com, mydomain.com for root domain)
• Username: the domain name containing the record (e.g. mydomain.com)
• Password: Concatenate the appropriate KEY and the Cloudflare API Token you created earlier. e.g., . The Key must be exactly 8 characters.
• Server: the Cloudflare Worker route <worker-name>.<worker-subdomain>.workers.dev
  • as of Unifi Network 7.0.25 this needs to be <worker-name>.<worker-subdomain>.workers.dev/nic/update?hostname=%h&myip=%i.

Acknowledgements

• inadyn is an open-source application that supports different dynamic DNS providers. It's used by UniFi OS under-the-hood to update your public IP address.
• inadyn-cloudflare much of the code for this project is taken from blackjid's project.
• Cloudflare Workers Basic Auth Example