private void setDefaultGW(){
		String GW = txtDefaultGW.getText();
                if(!GW.equalsIgnoreCase("Enter Default Gateway")){
                        if(!IPV4Address.validateDecIP(GW) && !GW.equals("")){
				lblError.setText("Invalid Default Gateway Address");
				lblError.setForeground(Color.RED);
				lblError.setVisible(true);
				controller.shakeDiaLog(this);
				ErrorFlag = true;
			}else{
				lblError.setVisible(false);
                                GW = txtDefaultGW.getText();
                                if(GW.equals("")) GW = null;
				DefaultGWAddress = GW;
				ErrorFlag = false;
			}
		}				
	}