DDNS4Me

A Dynamic DNS Command Line tool for use with Cloudflare

Overview

DDNS4Me is a basic CLI tool that allows updating of Cloudflare DNS "A" Records to reflect your current public IP address. It utilises the Cloudflare API to perform the DNS updating and a third-party service to identify your public IP address.

Usage

Common Usage

ddns4me --auth-path cfauth.json --zone dac9630aec642a428cd73f4be0a03569 --name my.example.org

Using a custom IP provider

ddns4me --auth-path cfauth.json --zone dac9630aec642a428cd73f4be0a03569 --name my.example.org --ip-provider https://echo.example.org

Using a custom TTL

ddns4me --auth-path cfauth.json --zone dac9630aec642a428cd73f4be0a03569 --name my.example.org --ttl 360

Command Line Arguments

Argument	Description
--auth-path	Required. Path to the authentication file that contains the authentication details.
--zone	Required. The Cloudflare Zone Identifier.
--name	Required. The DNS name to use in the zone.
--ttl	(Default: 120) The DNS record Time-to-Live (TTL) in seconds.
--ip-provider	(Default: https://icanhazip.com/) URL for service that returns your public IP as plain text.

Authentication

DDNS4Me requires a Cloudflare API token which needs to be stored in a JSON file to avoid the token itself being stored in shell logs.

{
    "CloudflareApiToken": "3706c7ce56fa785fe0e8e09c0c4bbacd"
}

To create your own Cloudflare API token, head to your account profile on Cloudflare then to the API Tokens page. From there, you need to create a token with the Edit zone DNS permission which Cloudflare has a template for.

Public IP Address Discovery

The third-party service for public IP addresses can be any service that returns your public IP as plain text from a HTTP request. By default, DDNS4Me will use icanhazip.com however you can specify your own via the --ip-provider command line argument.

For those that have privacy concerns or would like to control the IP provider themselves, it can be a straightforward task to make your own. Through something like Cloudflare Workers, available for free, you can build your own IP provider with code similar to this example:

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

/**
 * Respond to the request
 * @param {Request} request
 */
async function handleRequest(request) {
  return new Response(request.headers.get("cf-connecting-ip"), {status: 200})
}

It is entirely possible to build your own in any language on any Internet-available service - whether that be Azure Functions, AWS Lambda or some other hosting. The only thing it needs to do is echo-back as plain text the IP address of the client that made the request.