The issue with your setup is that you have:
- Android has it's mobile internet connection, via it's sim card and mobile antenna. This is acting as the network client, as far as Android is concerned. This interface lives on, say, network
- Android has a second connection, which is its hotspot connection. This is special in that Android has created a bridge between interface #1, and this one. Android doesn't offer an interface to alter the routing table for this new gateway (at least to the best of my knowledge). This interface lives on, say, network
- Your PC is connecting to interface #2, via it's own WiFi interface. It's being assigned an IP address by the gateway (
192.168.10.1 say, in this example). Let's say the PC gets assigned an IP address,
Now, Android will be using interface #1 to handle all of its level 3 and 4 networking needs (IP, TCP, UDP, etc.). There is no user access (again, AFAIK) to control anything networking-ee about interface #2.
Therefore, when you're using your Android device, you're attempting to access
192.168.10.23 (the PC), from interface #1
126.96.36.199 (Android mobile antenna).
The mobile antenna will not have a MAC address for this IP address in its ARP table, so it'll forward the message on to it's default gateway, say:
188.8.131.52 (your network operators router), to see if it knows where
192.168.10.23 (the PC) lives. It won't know, and the request will eventually be dropped.
The way to get around this, would be to:
- Configure interface #2 to forward outgoing requests (those that aren't in its network
192.168.10.0/24) on to
184.108.40.206 (your network operators router).
- Configure interface #1 to use interface #2 as it's default gateway.
Without root access this is a no go... But with root access, at least in theory, this should be possible, although, probably not worth the trouble. It would also need to be reset when the hotspot is turned off, otherwise your device will have no internet access.
Maybe an app exists to handle this somewhere? xda's site maybe? But I really don't know.
That's the problem you're facing though, if you want to look in to it further.