ddnsd 🌐

A lightweight dynamic DNS (DynDNS) daemon written in Go that periodically checks your local IP address and updates DNS records hosted at INWX via their API.

How it works ⚙️

1. On startup, the tool reads the configured network interface and fetches the current IP address.
2. It compares the address against the value already stored in the DNS record (cached locally to minimize API calls).
3. If the address has changed, it updates the corresponding AAAA (IPv6) record at INWX.
4. The check repeats at the configured interval until the process receives SIGINT or SIGTERM.

Note: Only IPv6 is currently supported. IPv4 support is planned.

Prerequisites 📋

• An INWX account with API access enabled.
• The DNS record (host.domain) must already exist in your INWX nameserver configuration before running this tool — it updates existing records, it does not create them.

Installation 🔧

git clone https://github.com/your-username/ddnsd.git
cd ddnsd
go build -o ddnsd .

Usage 🚀

ddnsd -c /path/to/config.yaml

The -c / --config flag is required and must point to a valid YAML configuration file.

Providers 🔌

The tool is built around two provider types that can be mixed and matched.

DNS providers

DNS providers are responsible for reading and updating DNS records.

Name	Description
inwx	Updates AAAA records via the INWX XML-RPC API.

Address providers

Address providers are responsible for retrieving the current IP address that should be set in DNS.

Name	Description
local	Reads the IPv6 address from a local network interface.

More providers for both sides are planned for future releases.

Configuration 📝

Create a YAML configuration file. An annotated example is provided in internal/examples/config.yaml.

# DNS provider settings
dnsProvider:
  name: inwx                 # Only "inwx" is supported
  username: your-api-user    # INWX API username
  password: your-api-password

# Address provider settings
addressProvider:
  name: local                # Only "local" is supported
  ipVersion: 6               # IP version to watch (only 6 is supported)
  options:
    iface: eth0              # Network interface to read the IPv6 address from

# DNS record to update
domain: example.com          # Your domain (zone)
host: myserver               # Hostname — the record updated will be myserver.example.com

# Behaviour
checkInterval: 60            # Seconds between checks (default: 10)
dryRun: false                # Set to true to log what would happen without making changes
loglevel: info               # One of: trace, debug, info, warn, error, fatal, panic

Configuration options

Key	Type	Default	Description
dnsProvider.name	string	—	DNS backend. Must be inwx.
dnsProvider.username	string	—	INWX API username.
dnsProvider.password	string	—	INWX API password.
addressProvider.name	string	—	Address source. Must be local.
addressProvider.ipVersion	int	—	IP version to track. Must be 6.
addressProvider.options.iface	string	—	Network interface name (e.g. eth0, wlp0s20f3).
domain	string	—	DNS zone (e.g. example.com).
host	string	—	Hostname part of the record (e.g. myserver).
checkInterval	int	10	Interval in seconds between IP checks.
dryRun	bool	false	When true, skips the actual DNS update.
loglevel	string	info	Log verbosity level.

Environment variables

All config values can be overridden via environment variables prefixed with DDNSD_. For example, to set the log level:

DDNSD_LOGLEVEL=debug ddnsd -c config.yaml

🔒 Security: Do not commit your configuration file if it contains credentials. Add config.yaml to your .gitignore.

Running as a systemd service 🖥️

Create /etc/systemd/system/ddnsd.service:

[Unit]
Description=INWX Dynamic DNS updater
After=network-online.target
Wants=network-online.target

[Service]
ExecStart=/usr/local/bin/ddnsd -c /etc/ddnsd/config.yaml
Restart=on-failure
RestartSec=10

[Install]
WantedBy=multi-user.target

Then enable and start the service:

sudo systemctl enable --now ddnsd

License 📄

See LICENSE.