Connect to desktop web server from mobile device

The problem

I hava a Java EE application running in my development enviroment, i.e, in a desktop PC. This PC is connected to my company LAN network by using an ethernet cable.
This application uses some advance signature functions, which requiere a third party app would be installed in the client device. In this case, this application is Autofirma (it can be download from here). In my desktop environment it works fine, but we must certificate it also works in mobile devices, like Android and iOS devices.
The problem is that in order to test this web application you need to must to it from the mobile device. At this time there is not a suitable wirless connection in the company which allows this kind of tests, so you have to come out with your own solution.
I´ve been checking ways to connect my mobile device to the PC via USB cable, but I did not found a valid or easy-to-make solution. So I will propose my low-technology solution.

Target scenario

My solution consists in connect the mobile device and the desktop PC via WI-FI, by using a third mobile device as WI-FI hotspot. It also requires a WI-FI dongle or a WI-FI card in the desktop PC.

This is the whole picture of the solution.

For this simple test, I will access to my Apache Web Server home page from the android tablet.

The full environment elenemts and caracteristis are as follows:

• Desktop PC (Development environment): Windows 7
• WI-FI dongle: Who cares
• Tester mobile device: Samsung Galaxy Tab 3
• WI-FI hotspot: Motorola Moto E

Set up

Wi-Fi hotspot

In Android is very easy to configure your device as a WI-FI hotspot. This is primary intended to let other devices use its 3G/4G connection via WI-FI.

Go to settings > More > Modem and Wi-Fi zone

There you must enable the Wi-Fi hotstpot and, optionally, set up your security settings.

Desktop PC 

In the desktop PC you need to plug the USB dongle and install all required drivers. Unless you are using an extremely cheap chinese dongle, windows will recognize and configure it for you.

In your network manager you will see two networks: the LAN network and the wirless network. For this last one, if you previously enable security settings in your Wi-Fi hotspot, you will have to introduce your password before the connection could be established.

Each network connection will have its own MAC and IP address. In my case, my "ETH IP" is 192.168.1.134 and my "WI-FI IP" is 192.168.43.239.

Tester mobile device

In the android tablet, you just need to select the Wi-Fi hotspot wirless network.

Test

In the desktop PC my Apache Web Server is running on port 80. So, if you go to http://localhost you will see it. But from the tester mobile device point of view, this IP address is 192.168.43.239.
So you need to access to http://192.168.43.239. 

Trouble shooting

In order to this scenario works you may need to disable/configure the desktop PC firewall.