mircopergreffi/cloudflare-ddns repository overview

https://github.com/mircopergreffi/cloudflare-ddns⁠

⁠Cloudflare DDNS

Simple C application wrapped into a container for updating Cloudflare DNS records.
It allows you to use Cloudflare as a Dynamic DNS.

The container is built from scratch and only contains the statically-linked executable and SSL certficates in order to minimize its footprint.

The compressed image size is 2.4MB.

A special thanks to @gmasini97⁠ for the contributions.

⁠How It Works

Waits for your public IP to change, it checks for changes with a set time interval (UPDATE_INTERVAL, see Environment Variables⁠).
The IP is checked using Cloudflare APIs (https://cloudflare.com/cdn-cgi/trace⁠).

Then deletes all DNS records, except for CNAME records if SKIP_CNAME is set to 1 (see Environment Variables⁠).

Generate new DNS records from the specified templates (BIND_TEMPLATE and BIND_TEMPLATE_NOPROXY, see Environment Variables⁠).

Set UPDATE_INTERVAL to a negative number (i.e.: -1) for updating the DNS records once and exiting.

When the container is started it will always udpate the records at least once.

⁠Resource Usage

The UNcompressed image size is 5.6MB.

RAM usage is roughly 1MB.

Network usage depends on how frequent you want to check for IP changes. Setting UPDATE_INTERVAL to 30 gives these consumptions:

• Data received: 720KB/h
• Data sent: 260KB/h

⁠Prerequisites

This documentation assumes you already have a Cloudflare account set up with a domain registered.

⁠Generate an API Token

1. Visit https://dash.cloudflare.com/profile/api-tokens⁠.
2. Click the "Create Token" button.
3. Use the template "Edit zone DNS".
4. In the "Zone Resources" section choose: "Include", "Specific Zone" and the zone.
5. Scroll to the bottom and click the "Continue to summary" button.
6. Click the "Create Token" button.
7. Copy your newly generate token.

⁠List your ZoneIDs

Open a terminal and type:

curl -X GET "https://api.cloudflare.com/client/v4/zones" \
     -H "Authorization: Bearer YOUR_TOKEN" \
     -H "Content-Type: application/json"

Replace YOUR_TOKEN with the previously generated token.

⁠Environment Variables

BIND_TEMPLATE and BIND_TEMPLATE_NOPROXY are used to generate Zone files (see: https://en.wikipedia.org/wiki/Zone_file⁠).
The DNS records generated from BIND_TEMPLATE are proxied from Cloudflare.
The DNS records generated from BIND_TEMPLATE_NOPROXY are NOT proxied from Cloudflare.
Template variables:

• %domain% is replaced with the content of the environment variable DOMAIN.
• %ip% is replaced with your public IP.
• ; is replaced with a new line.

⁠Docker

⁠Build the image yourself

Pull the repository:

$ git clone https://github.com/mircopergreffi/cloudflare-ddns
$ cd cloudflare-ddns

Create .env file from example.env and edit it:

$ cp example.env .env
$ vi .env

Build the image:

$ docker build -t cloudflare-ddns .

Run the image:

$ docker run -d --env-file .env cloudflare-ddns

⁠Prebuilt image

Create a .env file from the template (example.env).
Pull and run the image:

$ docker run -d --env-file .env \
    mircopergreffi/cloudflare-ddns