philippluettecke/ionos-dyndns repository overview

⁠Ionos-Dyndns for Docker

Keeps your domains at IONOS pointing to your current home IP address (Dynamic DNS).

Home internet connections usually get a new public IP address from time to time. This container checks your IP on a schedule you define and updates the DNS records of your domains whenever it changed. That way, myhome.example.com always reaches your home network.

It is a small Docker wrapper around the Python tool Domain Connect Dyndns⁠.

• Source code, issues and releases: https://github.com/philipp-luettecke/ionos-dyndns-docker⁠
• Supported architectures: linux/amd64, linux/arm64 (e.g. Raspberry Pi 4/5)

⁠Image tags

For automatic updates without surprises use 1. For fully reproducible setups pin an exact version like 1.2.3.

⁠What you need

• A computer or server that is always on (e.g. a Raspberry Pi, NAS or home server)
• Docker⁠ with Docker Compose installed
• A domain hosted at IONOS

⁠Quick start

1. Create a folder for the container and go into it:

   mkdir ionos-dyndns && cd ionos-dyndns
   

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2. Create a file named docker-compose.yml with this content:

   services:
     ionos-dyndns:
       image: philippluettecke/ionos-dyndns:latest
       container_name: ionos-dyndns
       restart: unless-stopped
       environment:
         - CRON_SCHEDULE=*/15 * * * *
         - TZ=Europe/Berlin
       volumes:
         - ./config:/config
       network_mode: host
       user: 1000:1000
   

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3. Create the config folder (it stores your domain settings and login tokens):

   mkdir config
   

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   The container runs as user 1000:1000 (the first normal user on most Linux systems). If you use a different user, adjust user: and make sure that user may write to ./config.

4. Start the container:

   docker compose up -d
   

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5. Add your domain (see the section "Adding a domain" below).

That's it. From now on the container updates your domains automatically and restarts itself after a reboot.

⁠Adding a domain

Run this once per domain, and replace <DOMAIN> with your domain, e.g. home.example.com:

docker exec -it ionos-dyndns domain-connect-dyndns setup --domain <DOMAIN>

The tool prints a link. Open it in your browser, log in to IONOS and confirm the access. Afterwards paste the requested code back into the terminal if asked. The result is saved in ./config/domains.txt.

⁠Settings

All settings are environment variables in the environment: section of docker-compose.yml.

After changing a setting, apply it with docker compose up -d.

⁠The update schedule (cron format)

CRON_SCHEDULE consists of five fields separated by spaces:

┌───────── minute (0-59)
│ ┌─────── hour (0-23)
│ │ ┌───── day of month (1-31)
│ │ │ ┌─── month (1-12)
│ │ │ │ ┌─ day of week (0-7, Sunday = 0 or 7)
│ │ │ │ │
* * * * *

* means "every", */15 means "every 15th".

If the expression is invalid, the container stops and prints an error in the log. All domains are additionally updated once every time the container starts.

⁠Everyday commands

Check what the container is doing (shows the update log):

docker logs ionos-dyndns
docker logs -f ionos-dyndns    # follow live, quit with Ctrl+C

Update a domain right now:

docker exec -it ionos-dyndns domain-connect-dyndns update --domain <DOMAIN>

Remove a domain:

docker exec -it ionos-dyndns domain-connect-dyndns remove --domain <DOMAIN>

Stop / start the container:

docker compose stop
docker compose start

Install a new version of the image:

docker compose pull
docker compose up -d

⁠Troubleshooting

• Container keeps restarting: run docker logs ionos-dyndns. Most often CRON_SCHEDULE is invalid or ./config is not writable for the configured user.
• "Permission denied" on domains.txt: the folder ./config must be writable by the user in user:. Fix with sudo chown -R 1000:1000 config.
• Wrong update times: check that TZ is set to your time zone.
• IONOS login expired: repeat the setup step (see "Adding a domain") for the domain.

⁠Security note

config/domains.txt contains access tokens for your IONOS account. Keep it private and never commit or share it. This repository ignores the config/ folder by default.

⁠Building the image yourself

git clone https://github.com/philipp-luettecke/ionos-dyndns-docker.git
cd ionos-dyndns-docker
docker compose up -d --build