mikrotik_duckdns_nat.rsc

:local Token "your-token"
:local Domain "subdomain"
 
:global PreviousIP
 
:log info ("DuckDNS: Checking IP")
/tool fetch mode=https url="https://api.ipify.org/" dst-path=ip.txt
:local ExternalIP [/file get ip.txt contents]
 
: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")
}