Hey there! 👋
In this blog post, I will be showing you how to use Cloudflare as a Dynamic DNS (DDNS) provider.
What is DDNS?
Dynamic DNS (DDNS) is a service that keeps the Domain Name System (DNS) updated with a web property’s correct IP address.
Cloudflare glossary: Dynamic DNS 1
Essentially, DDNS allows you to automatically update your domain’s DNS records when a change is detected to your home’s public IP address.
DDNS Use Case
Many Internet Service Providers (ISPs) do not provide a static IP address with their regular consumer plans. This often causes issues for those of us that enjoy self-hosting applications from home.
Say you’re self-hosting some applications from home and have DNS records pointing to your home’s public IP address. What if your router suddenly rebooted due to a software or hardware issue?
Your ISP may assign you with a new public IP address causing your applications to be inaccessible 😰 This is an example of where DDNS could help.
With DDNS, you can ensure your DNS records are automatically kept up to date when your home’s public IP address changes 👍
Other DDNS providers
Cloudflare is not the only option for DDNS. There are many others including:
However, for this blog post, we are obviously focusing on using Cloudflare 😄
Using Cloudflare as a DDNS provider
We will be using joshuaavalon’s docker-cloudflare container to use Cloudflare as a DDNS provider.
There are many Cloudflare DDNS containers out there. The reason I use this one is because:
It’s multi-architecture meaning the container image can run on amd64, ARM/v6, ARM/v7 and ARM64 based devices.
- ARM FTW! 🥧
It has a minimal configuration file supporting YAML, JSON or JavaScript. Configuration via environment variables is also supported but is considered “legacy”.
It provides advanced configuration options such as using an IPv(4|6) lookup service of your choice, and Webhooks to notify when DNS record updates run, succeed or fail.
Prerequisites
Docker installed on the device which can reach the Cloudflare API:
https://api.cloudflare.com/client/v4/A Cloudflare API token. Please follow the instructions here.
Make sure you generate an API Token and not a Global API Key!
Using the docker-cloudflare container
The minimal configuration file required for the docker-cloudflare container is the following:
# config.yaml
auth:
# Provide your API token here!
scopedToken: QPExdfoNLwndJPDbt4nK9-yF1z_srC8D0m6-Gv_h
domains:
# Remember to change this to your domain!
- name: ddns.yourdomain.com
# The type of record that is created
type: A
# Determines the proxy status for the record
proxied: true
# If the record does not exist, create it
create: true
# zoneId could also be yourdomain.com if the Cloudflare API token is granted #zone:read permissions
zoneId: JBFRZWzhTKtRFWgu3X7f4YLX
The container will update your DNS record with your public IP address every 5 minutes.
Once you have your configuration file, use the following command to start the docker-cloudflare container:
docker run --name cloudflare-ddns -d -v ./config.yaml:/app/config.yaml joshava/cloudflare-ddns
Once started, you should see something similar to the following when running docker logs cloudflare-ddns:
[cont-init.d] executing container initialization scripts...
[cont-init.d] 10-adduser: executing...
usermod: no changes
Initializing container
User uid: 1001
User gid: 1001
[cont-init.d] 10-adduser: exited 0.
[cont-init.d] 11-cron: executing...
Setting crontab to */5 * * * *
[cont-init.d] 11-cron: exited 0.
[cont-init.d] done.
[services.d] starting services
[services.d] done.
2021-09-16T18:02:57.903Z [info] Cloudflare DDNS start
2021-09-16T18:03:00.026Z [info] Skipped updating.
2021-09-16T18:03:00.027Z [info] Updated ddns.yourdomain.com with <your public IP>
2021-09-16T18:03:00.028Z [info] Cloudflare DDNS end
Congratulations, you’re now using Cloudflare as a DDNS provider! 😄 ⭐
Bonus - Using a Discord Webhook for updates
A few months ago I looked into using Discord webhooks to receive updates for when my DNS records were updated by the container.
I submitted a PR because I wanted to send a specific message along with the webhook payload. After discussion with the author, a webhook formatter was added which I tested using a Discord webhook.
Firstly, you need to create a Discord webhook for a channel on your server. Once created, provide the webhook URL in the config below.
To use the formatter, you need to use a JavaScript configuration file similar to the following:
// config.js
const formatter = (status, data) => {
if (status === "run") {
return { content: "Updating DNS record." };
} else {
return { content: JSON.stringify(data) };
}
};
const config = {
auth: {
scopedToken: "QPExdfoNLwndJPDbt4nK9-yF1z_srC8D0m6-Gv_h"
},
domains: [
{
// Remember to change to your domain!
name: "ddns.yourdomain.com",
type: "A",
proxied: true,
create: true,
// Remember to change the zone ID!
zoneId: "JBFRZWzhTKtRFWgu3X7f4YLX",
webhook: {
// Make sure you edit the webhook URL below to your own!
run: "https://discord.com/api/webhooks/111111233445566678/py-D6zAc4IolXBoA7gslLAJc0WKO3KPU1eOxSNzX6qlkCBsqIP8EGILj-ALraivIbs6n",
success: "https://discord.com/api/webhooks/111111233445566678/py-D6zAc4IolXBoA7gslLAJc0WKO3KPU1eOxSNzX6qlkCBsqIP8EGILj-ALraivIbs6n",
failure: "https://discord.com/api/webhooks/111111233445566678/py-D6zAc4IolXBoA7gslLAJc0WKO3KPU1eOxSNzX6qlkCBsqIP8EGILj-ALraivIbs6n",
formatter
}
}
]
};
module.exports = config;
As the configuration file has changed from YAML to JavaScript, the docker run command used before is slightly different: docker run --name cloudflare-ddns -d -v ./config.js:/app/config.js joshava/cloudflare-ddns
Once running, you should see messages appearing in the Discord channel when a DNS record update occurs!
I hope you found this blog post useful! Until next time! 😄