# IONOS DDNS Auto-Updater & Creator

A Python-based system service that automatically updates DNS records on IONOS. Unlike standard DDNS scripts, this solution uses the **IONOS REST API**, allowing it to:
1. **Update** existing DNS records.
2. **Create** new DNS records automatically if they don't exist.
3. Check the current DNS value before updating to avoid API rate limits.

## Features
- **Smart Check:** Compares public IP with current DNS resolution before sending API requests.
- **Auto-Discovery:** Automatically detects which DNS Zone a subdomain belongs to.
- **System Service:** Runs as a background `systemd` service with crash protection.
- **Logging:** Detailed logs in `/var/log/ionos-ddns.log`.

## Prerequisites
- Python 3
- An IONOS account with access to the "Developer API".
- An API Key (Prefix + Secret) generated at [developer.hosting.ionos.com](https://developer.hosting.ionos.com/).

## Installation

### 1. Clone the repository to `/opt`
It is recommended to install this in a system directory.

```bash
sudo mkdir -p /opt/ionos-ddns
cd /opt
sudo git clone https://git.invelio.co.uk/rafal/ionos-ddns.git
cd /opt/ionos-ddns

```

### 2. Install dependencies
```
sudo apt update
sudo apt install python3-pip
sudo pip3 install -r requirements.txt
```

### 3. Configuration
```
sudo nano config.json
```
Fill in your api_prefix and api_secret.

Domains List: Edit domains.txt and add domains one per line:
```
sudo nano domains.txt
```
Example:
```
mydomain.com
vpn.mydomain.com
server.other-domain.net
```
IMPORTANT: Secure your API keys! Since config.json contains sensitive credentials, restrict access to it so only the root user can read it:
```
sudo chown root:root /opt/ionos-ddns/config.json
sudo chmod 600 /opt/ionos-ddns/config.json
```

Make script executable:
```
sudo chmod +x /opt/ionos-ddns/update_ddns.py
```

### 4. Install System Service
Copy the service file to systemd directory:
```
sudo cp ionos-ddns.service /etc/systemd/system/
```
Reload daemon, enable and start the service:
```
sudo systemctl daemon-reload
sudo systemctl enable ionos-ddns.service
sudo systemctl start ionos-ddns.service
```

### Monitoring
Check the service status:
```
sudo systemctl status ionos-ddns.service
```
View logs:
```
tail -f /var/log/ionos-ddns.log
```

### How it works
The script runs in an infinite loop (every 10 minutes).

Fetches your current Public IP.

Reads domains.txt.

For each domain:

Finds the correct Zone ID via API.

Checks if an A-Record exists.

If exists: Checks if IP matches. If not, performs PUT (Update).

If missing: Performs POST (Create).

### ERROR
This error (400 Invalid API key format) means that the IONOS server rejected the key because its structure is incorrect.
The most common causes are:
Extra spaces (accidentally copied when pasting).
Manually adding a dot in the config file (the script adds the dot automatically).
Using the wrong type of key (Cloud API key instead of Hosting/DNS API key).
Here is how to fix it step by step.
```
sudo nano /opt/ionos-ddns/config.json
```
Make sure the quotation marks are placed directly against the characters, with no spaces.
WRONG (note the spaces):
```
"api_prefix": " 23498723498 ",
"api_secret": " a1b2c3d4 "
```
CORRECT:
```
"api_prefix": "23498723498",
"api_secret": "a1b2c3d4"
```
STEP 2: Do not add a dot in config.json
The Python script contains this line:
```
"X-API-Key": f"{prefix}.{secret}"
```
It automatically joins these two values with a dot.
If you entered in config.json something like:
prefix: "myPrefix."
then the script sends:
"myPrefix..secret" (two dots), which causes the error.
api_prefix: Only the first part of the key.
api_secret: Only the second, long part of the key.