DDNS Client DuckDNS

DDNS Client DuckDNS

This article describes a custom configuration that uses a user-defined update URL.

In most cases you can follow a much simpler setup process by selecting “duckdns.org” as your Service provider in DDNS client.

Use of the instructions below assumes you have ddns-scripts installed.

Following the link under the “Hints” header can show you if there are any changes that might be helpful, including features that aren't always present in busybox.
Installing the ca-certificates package will automatically add a general collection of certificates to the directory /etc/ssl/certs/ and enables verification of SSL certificates by any program that uses this as a default, including ddns-scripts.

IPv4

In /etc/config/ddns, replace <subdomain> and <duckdns-token> with the proper values.

config service 'DuckDNS_ipv4'
	option enabled		'1'
	option interface	'wan'
	option username		'<subdomain>'
	option domain		'<subdomain>.duckdns.org'
	option password		'<duckdns-token>'
	option ip_source	'network'
	option ip_network	'wan'
	option check_interval	'1'
	option check_unit	'hours'
	option update_url	'https://www.duckdns.org/update?domains=[USERNAME]&token=[PASSWORD]&ip=[IP]'
	option use_https	'1'

Notes

This will update anytime the wan network goes up, or the check (every hour) notices an inconsistency, and will force the ip to the value detected on the wan network (remove the &ip=[IP] and duckdns will auto-detect).
The interface option tells ddns to update when this network changes status, namely when it goes up.
The domain option is the domain held by the client, and 'nslookup $DOMAIN' should succeed and point to the client (or router it's behind) when everything is up to date; this is used as the check to see if $DOMAIN points to the clients public IP.
The username option is used where the domain option was used before, this is also reflected in the change to update_url
Turning on https for improved security, using /etc/ssl/certs/ (populated by “ca-certificates”), or “option cacert”
The force_interval and force_unit options are unnecessary as duckdns does not expire listings if they aren't refreshed periodically.
TIP: If you are behind Double-NAT (eg. your ISP modem is in Router mode, and no option to change it to Bridge mode), you can make following changes according to DuckDNS installer guide (OpenWrt section)
```
    option ip_source   'web'
    option ip_url      'http://ipv4.wtfismyip.com/text' 
```

If you want to view or edit the service in LuCI (via luci-app-ddns), it is also necessary to add these options to the config:

    option lookup_host	'<subdomain>.duckdns.org'
    option use_ipv6		'0'
    option cacert		'/etc/ssl/certs'

IPv6

ddns-scripts supports updating your duckdns.org subdomain with your IPv6 address, which is still needed for home users with dynamic IPv6 address. Even though your IPv6 address is globally addressable, as of 2024, some residential ISP still assign dynamic IPv6 address that may periodically change.

In /etc/config/ddns, replace <subdomain> and <duckdns-token> below with the proper values.

config service 'DuckDNS_ipv6'
	option enabled		'1'
	option lookup_host	'<subdomain>.duckdns.org'
	option username		'<subdomain>'
	option domain		'<subdomain>.duckdns.org'
	option password		'<duckdns-token>'
	option use_ipv6		'1'
	option ip_source	'network'
	option ip_network	'wan6'
	option interface	'wan6'
	option check_interval	'1'
	option check_unit	'hours'
	option update_url	'https://www.duckdns.org/update?domains=[USERNAME]&token=[PASSWORD]&ipv6=[IP]'
	option use_https	'1'

Enable “Use cURL” in DDNS Global Settings to avoid GNU Wget Error: 4 error

config ddns 'global'
    option use_curl '1'

Table of Contents

DDNS Client DuckDNS

IPv4

IPv6

Further Reading