void loop ( ) {

    int noBytes = Udp.parsePacket();
    String received_command = " ";

    if ( noBytes ) {
        Udp.read(packetBuffer,noBytes);
        for (int i=1;i<=noBytes;i++){
            received_command += char(packetBuffer[i - 1];
        }

        int dac_value;
        dac_value = received_command.toInt(); // str to int

        Serial.print("adc value: ");
        Serial.println(dac_value);

        //## how to send dac_value to mcp4725 for take analog out this section !?!? ##
    }
}