Cloudflare Dynamic DNS backend for Inadyn

This is a small application that exposes an inadyn compatible API and uses Cloudflare's API to update the IP of one of your DNS A records.

inadyn is an open-source application that supports different dynamic DNS providers. It's used by the UDM/UDM-pro Unifi OS under the hood to update your public IP.

Why?

I have an Unifi Dream Machine, and I want to update my home DNS when my IP changes. But the Unifi controller dynamic DNS service doesn't support Cloudflare as one of the providers. I hope this is a temporary solution as version 2.6 of Inadyn already natively support Cloudflare.

Create and deploy the worker

We'll use Cloudflare's wrangler CLI to build and deploy the service worker.

You can run the following steps on your computer. You don't need to ssh into the UDM terminal.

1. Install. Wrangler Installation

   # Install
   npm install -g @cloudflare/wrangler
   

2. Config wrangler by following the instructions. You will need to create an API key with permissions to deploy a worker.

   wrangler config

   TIP: Use the "Edit Cloudflare Workers" Template, choose "All accounts and the zone you will use.

   Copy the API key, and paste it in the terminal to complete the command above.

Deploy the worker

You need to add your account id to the provided wrangler.toml file. You can get it from the Cloudflare manage worker page (on the sidebar)

1. Enable your workers subdomain. This is a subdomain on where the inadyn worker will be exposed.

   wrangler subdomain <worker-subdomain>

2. Publish the worker

   $ wrangler publish
   ✨  Built successfully, built project size is 12 KiB.
   ✨  Successfully published your script to
   https://dyndns.<worker-subdomain>.workers.dev

   TIP: That hostname will be used on the next step on the Unifi UI

3. Create another API token so the worker can update your records. Go to https://dash.cloudflare.com/profile/api-tokens and select "Create custom token"

   On the permission section, select

   

   Copy the API key. You will use it as password in the next step

Setup Unifi controller

Go to your unifi controller Dynamic Dns section and setup the following

• service: choose anything, it doesn't matter
• hostname: the name of the record you want to update (e.g. subdomain.mydomain.com)
• username: the name of the zone where the record is defined. (e.g. mydomain.com)
• password: a Cloudflare api token with dns:edit and zone:read permissions
• server: the Cloudflare Worker DNS plus the path dyndns.<worker-subdomain>.workers.dev/update?hostname=%h&ip=%i

Note: you might need to escape an extra slash between the hostname of your worker and the path due to a bug in the controller ui. dyndns.<worker-subdomain>.workers.dev/\/update?hostname=%h&ip=%i At least as of UDM controller version 6.1.71 you no longer need this

Debugging

You can login into you UnifiOS terminal and run the following command to se how the configuration is working.

inadyn -1 -l debug -n -f /run/inadyn.conf

You can also look at the logs from the background process from the UDM

cat /var/log/messages | grep inadyn