Gandi DDNS

This is a simple script for updating a DNS record in a zone hosted at Gandi (in LiveDNS) to match the current public IP address of the system on which it's run.

Installation

Checkout the GIT repository to a suitable directory, and then create a Python virtual environment:

cd /usr/local
git clone https://github.com/dpage/gandi-ddns.git
cd gandi-ddns
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

Configuration

You will need a Gandi API key. To get that (correct as of January 5th 2024):

Login to Gandi
Click your account name in the header, and select User Settings.
Click the View my Personal Access Tokens button.
Click the Create a token button.
Select the appropriate organisation and click Next.
Enter a token name, and select the expiry period.
Under Token resources, select Restrict to selected products.
Select the domain name.
Enable the options for Manage domain name technical configurations and See and renew domain names.
Click Create.

You will be shown the token but only once, so make sure you make a note of it!

Now make a copy of config.json.in and call it config.json. Edit config.json, and set the hostname, domain, and API key. You can also change the TTL for the DNS record if required.

Note: You should secure the configuration file against prying eyes, for example:

chmod 600 config.json

Running

Simply run the script under the Python virtual environment, for example:

/usr/local/gandi-ddns/venv/bin/python3 /usr/local/gandi-ddns/gandi-ddns.py 
2024-01-05 11:17:30.702259: Checking: ddns.example.com
    Current IP: 10.1.2.3
    DNS IP:     
    Updating DNS records at Gandi...
    DNS updated.

It may take a minute or two for Gandi's public facing DNS servers to catch up. Once they have, run the script again (it won't hurt to do it earlier - it'll just try to re-create/update the record again):

/usr/local/gandi-ddns/venv/bin/python3 /usr/local/gandi-ddns/gandi-ddns.py 
2024-01-05 11:20:57.022458: Checking: ddns.example.com
    Current IP: 10.1.2.3
    DNS IP:     10.1.2.3
    No IP address change detected.

Note that if the API key is incorrect or other errors occur, you will see output similar to:

2024-01-05 11:21:50.492538: Checking: Checking: ddns.example.com
    Current IP: 10.1.2.3
    DNS IP:     
    Updating DNS records at Gandi...
    Unexpected response updating DNS at Gandi: 500 - The server has either erred or is incapable of performing the requested operation.

Check that everything looks good in your zone in the LiveDNS web interface, and assuming it is, setup a cron job to run the script every minute or so.