ddnsclient/README.md

# ddnsclient

This application can be use to update dynamic hostnames. Currently it implements the following DynDNS providers:

- ddnss.de
- duckdns.org

This project uses Quarkus.

## Configuration

ddnsclient requires a configuration in json format. It expects to find a file `config.json` in its working directory.
The configuration can contain a list of update targets:

```
[
  {
    "provider": "<dyndns-provider>",
    "username" : "<username>",
    "password" : "<password>",
    "token": "<update-token>",
    "hostname": "<dynamic-hostname>"
  }
]
```

Depending on your dyndns provider you can either use `username`/`password` or `token` in a configuration.

ddnssclient can also be configured using some properties or environment variables

| Property                    | Environment variable        | Value                             | Default       |
|-----------------------------|-----------------------------|-----------------------------------|---------------|
| ddnsclient.interval         | DDNSCLIENT_INTERVAL         | e.g. "3600s", "60m", "1h"         | "5m"          |
| ddnsclient.ip-provider      | DDNSCLIENT_IP_PROVIDER      | an ip lookup provider (see below) | null (random) |
| ddnsclient.dns.resolver     | DDNSCLIENT_DNS_RESOLVER     | e.g. "9.9.9.9", "1.1.1.1"         | "9.9.9.9"     |
| ddnsclient.backoff-duration | DDNSCLIENT_BACKOFF_DURATION | e.g. "60s", "1m"                  | "300s"        |
| ddnssclient.config-file     | DDNSCLIENT_CONFIG_FILE      | e.g. "/path/to/your/config.json"  | "config.json" |

## IP lookup

In order to update a hostname, ddnsclient needs to know about the current public ip addresses of the machine it runs on.
For this, it uses one of the following ip lookup providers:

- ifconfig.me
- ipify.org
- ident.me
- nnev.de
- icanhazip.com

If no specific provider has been configured (see above), each request chooses a random provider from this list.