DuckDNS

This is an Ansible role for updating DuckDNS when

1. a network interface changes its IP address - it hooks into the DHCP client and updates the given DuckDNS record whenever the IP address of the given device changes.
2. every five minutes, as recommended by DuckDNS.

Configuration

All of the following variables must be present:

duckdns:
  interface:
  domain:
  token:

Get domain and token from duckdns.org. interface is the local device interface of which you'd like to publish its address to DuckDNS, e.g. wlan0 or eth0.

Debugging

• Show the local IP address with ip -4 a show dev wlan0

• Force renewal of IP address with sudo dhclient wlan0

• Check the log file in /var/log/duckdns.log

• There is a debug script in /etc/dhcp/dhclient-enter-hooks.d/debug which produces output like this:

  Sun Jun 28 11:11:07 CEST 2020: entering /etc/dhcp/dhclient-enter-hooks.d, dumping variables.
  reason='PREINIT'
  interface='wlan0'
  --------------------------
  Sun Jun 28 11:11:07 CEST 2020: entering /etc/dhcp/dhclient-exit-hooks.d, dumping variables.
  reason='PREINIT'
  interface='wlan0'
  --------------------------
  Sun Jun 28 11:11:07 CEST 2020: entering /etc/dhcp/dhclient-enter-hooks.d, dumping variables.
  reason='BOUND'
  interface='wlan0'
  new_ip_address='192.168.8.102'
  new_network_number='192.168.8.0'
  new_subnet_mask='255.255.255.0'
  new_broadcast_address='192.168.8.255'
  new_routers='192.168.8.1'
  new_domain_name_servers='192.168.8.1 192.168.8.1'
  --------------------------
  Sun Jun 28 11:11:07 CEST 2020: entering /etc/dhcp/dhclient-exit-hooks.d, dumping variables.
  reason='BOUND'
  interface='wlan0'
  new_ip_address='192.168.8.102'
  new_network_number='192.168.8.0'
  new_subnet_mask='255.255.255.0'
  new_broadcast_address='192.168.8.255'
  new_routers='192.168.8.1'
  new_domain_name_servers='192.168.8.1 192.168.8.1'
  --------------------------