mikrotik_duckdns.rsc

:local Token "your-token"
:local Domain "subdomain"
:local WanInterface "ether1"
 
:global PreviousIP
:global ExternalIP
 
:log info ("DuckDNS: Checking IP")
:local CurrentIP [/ip address get [/ip address find interface=$WanInterface ] address];
:set ExternalIP [:pick $CurrentIP 0 [:find $CurrentIP "/"]];
 
:if ($ExternalIP != $PreviousIP) do={
    :set PreviousIP $ExternalIP
    /tool fetch mode=https url="https://www.duckdns.org/update?domains=$Domain&token=$Token&ip=$ExternalIP" keep-result=no
    :log info ("DuckDNS: IP updated to $ExternalIP")
} else={
    :log info ("DuckDNS: IP not changed")
}