Ionos DNS updates

A simple script used to send dynamic DNS updates to the Ionos API. Using this script requires you to have your domain registered with Ionos, and having obtained an API key from them.

Dependencies

Python 3.6 or above.

Required python libraries:

• requests
• pyyaml

Configuration

Configuration of your DNS updates is declared inside the file config.yml. Once modified, this file must be kept secret. If your API key or your DNS update URL leaks to a bad actor, anyone visiting your domains runs the risk of being DNS-poisoned.

First, you will need to write your Ionos API keypair into the config file. Paste the respective values of your Ionos API-keypair into the config as follows:

apikey:
  prefix: <your api key prefix>
  secret: <your api key secret>

Next, add every domain you wish to send an update for to the domains list. The script will set a global DNS record for each listed domain and have it point to the local host's public IP address. The domains list should have the following format:

domains:
  - example.com
  - subdomain1.example.com
  - subdomain2.example.com

NOTE: Make sure you have manually added each subdomain you are listing in your Ionos account. The script currently does not handle adding subdomains for you. Attempting to update the DNS entry for an unregistered domain will cause the API call to fail.

You may optionally set a descriptive string which is sent along with the update:

description: "Dynamic DNS update."

As of right now, I am actually not sure what the description is needed for, but the API requires it to be present in the request. The value displayed here is used by default if you don't override it in config.yml.

Regular DNS updates

In order to keep your DNS records synchronized with your public IP address, you should run the update script periodically. As of this writing, Ionos limit dynamic DNS updates via API to 2 requests per minute, so don't send requests more frequently than that.

In order to update your DNS IPs once every minute, call the script once a minute. (Duh!) You can set your crontab to the following to achieve this:

*/1 * * * * /path/to/dnsupdate.py

Just make sure that the script is executable by the user whose cronjob is executing it, and that config.yml is listed in the same directory as the script itself. Run it manually at least once to make sure that everything is working. If the script runs without throwing an exception, everything worked and your DNS records now point to your public IP.