CloudFlare DDNS setup guide

Trap

CloudFlare Docs for DDNS recommends using DDClient, however API1 (www.cloudflare.com) used by DDClient is already deprecated. Thus DDClient is not usable for CloudFlare right now and even if you dig on forums, there are no recent solutions. You will run into the HTTP 403 (The CloudFlare "You are blocked" page) trouble when using DDClient cloudflare protocol, plus it does not log any error on it (you will need -verbose -debug and read all the HTTP response bodies to learn about this failure).

Good approach for now

CloudFlare-DDNS prodives a lightweight python script for auto update IP addresses.

Setup Docker

:warn: Running docker as non-root user is not covered in this solution.

curl -fsSL get.docker.com -o get-docker.sh && sh get-docker.sh
sudo apt install docker-compose -y

Setup CloudFlare-DDNS

mkdir -p ~/cloudflare-ddns
cd ~/cloudflare-ddns

Create an API Token in CloudFlare Profile with DNS-Edit permission.

Create these files

config.json

{
  "cloudflare": [
    {
      "authentication": {
        "api_token": "<Your API Token in CloudFlare Profile>"
      },
      "zone_id": "<Your Zone ID for the domain>",
      "subdomains": [
        {
          "name": "<subdomain name, leave empty for root>",
          "proxied": <true|false>
        }
      ]
    }
  ],
  "a": true,
  "aaaa": false,
  "purgeUnknownRecords": false,
  "ttl": 300
}

Note: leave "aaaa": false for Google Cloud VM as it does not support IPv6 by default.

docker-compose.yml

version: '3'
services:
  cloudflare-ddns:
    image: timothyjmiller/cloudflare-ddns:latest
    container_name: cloudflare-ddns
    security_opt:
      - no-new-privileges:true
    network_mode: 'host'
    environment:
      - PUID=1000
      - PGID=1000
    volumes:
      - /home/<user-name>/cloudflare-ddns/config.json:/config.json
    restart: unless-stopped

Note: always specify the absolute path instead of ~ if you are using sudo docker-composer.

sudo docker-compose up -d
sudo docker logs cloudflare-ddns

If success,

sudo systemctl enable docker

If failed, after editing any config,

sudo docker-compose down