Docker Cloudflare DDNS image will allow us to use the free CloudFlare DNS Service as a Dynamic DNS Provider (DDNS). So, In this article, we’ll dig a bit deeper into the details.

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Let’s take a closer look at Docker cloud-flare DDNS.

Docker Cloudflare DDNS

Cloudflare DDNS is a Docker image that automatically updates DNS records on Cloudflare. However, this small Alpine Linux-based Docker image allows us to use CloudFlare’s free DNS service as a dynamic DNS provider (DDNS).

Most importantly, this is a multi-arch image that will run on devices like the Raspberry Pi that are amd64, aarch64, and armhf.

Image Variants

Usage

The setup is simple.

docker run \
  -e API_KEY=xxxxxxx \
  -e ZONE=example.com \
  -e SUBDOMAIN=subdomain \
  oznu/cloudflare-ddns

Parameters

• --restart=always – After the host reboots, this makes sure the container restarts automatically.
• -e API_KEY – Our Cloudflare API token with a specific scope. See the section below on how to create a Cloudflare API token. Required

  API_KEY_FILE – From where we’ll get our Cloudflare scoped API token. API_KEY_FILE takes precedence if both API_KEY_FILE and API_KEY are there.

• -e ZONE – The DNS zone should receive DDNS updates. Required

  ZONE_FILE – From where we want to load our Cloudflare DNS Zone. If we specify both ZONE FILE and ZONE, ZONE FILE takes precedence.

• -e SUBDOMAIN– A subdomain of the zone where DNS changes can be made. If this is not there, the root zone will be used.

  SUBDOMAIN_FILE – The path from which our Cloudflare DNS Subdomain is loaded. SUBDOMAIN_FILE takes precedence if both SUBDOMAIN_FILE and SUBDOMAIN are there.

Optional Parameters

• -e PROXIED – If true, traffic will be routed through the Cloudflare CDN. false is the default value.
• -e RRTYPE=A – To use IPv6 records instead of IPv4 records, set AAAA. For IPv4 records, it defaults to A.
• -e DELETE_ON_STOP – If true, the dns record will be deleted when the container is stopped. false is the default value.
• -e INTERFACE=tun0 – Set to tun0 to get the IP address from a tun0 network interface. If this field is left blank, the public IP address will be used instead. The --network host run argument is required.
• -e CUSTOM_LOOKUP_CMD="echo '1.1.1.1'" – Set to any shell command to execute them, with the IP retrieved from the standard output. To use the default IP address detection methods, leave it unchecked.
• -e DNS_SERVER=10.0.0.2– Set the IP address of the DNS server we’d like to use to this value. Otherwise, it falls back to 1.1.1.1.
• -e CRON="@daily" – Before the exec portion, set our own custom CRON value. Defaults value is set to every 5 minutes – */5 * * * *.

Depreciated Parameters

• -e EMAIL – When using an Account-level token, our CloudFlare email address is used. When using a scoped API token, this variable MUST NOT be set.

Creating a Cloudflare API token

Go to Dashboard > profile > api-tokens and follow these steps to create a CloudFlare API token for the DNS zone:

1. Firstly, To create a token, click the Create Token button.
2. Secondly, Give the token a name. For example, cloudflare-ddns
3. Permissions should be granted to the token as follows:
   Read permissions for Zone-Zone Settings
   Read permissions for Zone-Zone
   Edit permissions forZone – DNS
4. After that, set the resources for the zone to:
   Include – All zones
5. Further, Complete the wizard and paste the generated token into the container’s API_KEY variable.

Multiple Domains

Create CNAME records in CloudFlare if we need multiple records pointing to the public IP address.

IPv6

Set the environment variable RRTYPE=AAAA if we want to set IPv6 records.
Moreover, we’ll also need docker with IPv6 support or a container with host networking enabled.

Docker Compose

On the other hand, if we use Docker Compose, follow these steps:

version: '2'
services:
  cloudflare-ddns:
    image: oznu/cloudflare-ddns:latest
    restart: always
    environment:
      - API_KEY=xxxxxxx
      - ZONE=domainname.com
      - SUBDOMAIN=subdomain.domainname.com
      - PROXIED=false

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Conclusion

In conclusion, Docker Cloudflare DDNS is a simple Docker image that wraps an example script to dynamically update a Cloudflare DNS record.