private void checkForDefaultSubnet(){
		String tempip = txtIpAddress.getText();
		
		if(txtSubnetMask.getText().equals("Enter Subnet Mask") || txtSubnetMask.getText() == null || txtSubnetMask.getText().equals("0.0.0.0")){
			String tempSubnet = IPV4Address.getDefaultSubnetMask(tempip);
			txtSubnetMask.setText(tempSubnet);
                        
			txtSubnetMask.setEnabled(true);
        }
		
        btnOk.setEnabled(true);
		
	}