:global ddnsuser "your_changeip_account"
:global ddnspass "your_changeip_password"
:global ddnshost "your_changeip_ddns_name"
:global ddnsip
:global ddnslastip [:tostr [:resolve $ddnshost] ]
:if ([ :typeof $ddnslastip ] = nil ) do={ :global ddnslastip "0" }
:global ddnsinterface "your_interface_name"
:global ddnssystem ("mt-" . [/system package get system version] )

:local int

:local ddnsipfn [ /ip address get [/ip address find interface=$ddnsinterface ] address ]
:global ddnsip [:pick $ddnsipfn 0 [:find $ddnsipfn "/"]]

:if ([ :typeof $ddnsip ] = nil ) do={
:log info ("DDNS: No ip address present on " . $ddnsinterface . ", please check.")
} else={

:if ($ddnsip != $ddnslastip) do={

:log info "DDNS: Sending ADSL UPDATE!"
:log info [ :put [/tool dns-update name=$ddnshost address=$ddnsip key-name=$ddnsuser key=$ddnspass ] ]
:global ddnslastip $ddnsip

} else={
:log info "DDNS: No ADSL update required."
}

}