Duck DNS Update Script For Mikrotik

# Duck DNS Update Script for MikroTik RouterOS 5.26 behind NAT

#--------------- Change Values in this section to match your setup ------------------

:local ducktoken "your-token"
:local duckdomain "your-domain"
:local ddnshost "$duckdomain.duckdns.org"

#------------------------------------------------------------------------------------
# No more changes need

:local ipddns [:resolve $ddnshost]

/tool fetch mode=http address="icanhazip.com" src-path="/" dst-path="/icanhazip.txt"
:delay 3
:local result [/file get icanhazip.txt contents]

:local resultLen [:len $result]
:local endLoc [:find $result "\n" -1]
:local ipfresh [:pick $result 0 $endLoc]
:log info "Duck DNS: IP detected from icanhazip.com is $ipfresh"

:if ($ipddns != $ipfresh) do={
    :log info "Duck DNS: Old IP is $ipddns"
    :log info "Duck DNS: New IP is $ipfresh"
    /tool fetch url="http://www.duckdns.org/update\?domains=$duckdomain&token=$ducktoken&ip=$ipfresh" dst-path=duckdns.txt
    :global ipddns $ipfresh
    :log info "Duck DNS: IP updated to $ipfresh!"
    } else={
     :log info "Duck DNS: Current IP is $ipddns"
     :log info "Duck DNS: Detected IP is same with current IP, dont need changes"
    }
}

source : http://wingloon.com/2014/06/28/duck-dns-update-script-for-mikrotik-routeros-5-26-behind-nat/