public DHCPDetect(){
        try {
            this.localIpAddress = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        serverIdentifier = null;
        // fill client identifier: HTYPE MACAddress
        clientIdentifier = new byte[1+LocalMacAddress.length];
        clientIdentifier[0] = DHCPConstants.HTYPE_ETHER;
        for (int i=0; i<LocalMacAddress.length; i++)
            clientIdentifier[i+1] = LocalMacAddress[i];

    }