I currently find myself in a situation where I need to find a NAT solution for a rooted Android 2.2 device other than IPTABLES, since I am stuck on using a particular ROM that doesn't support IPTABLES.
I need said Android device to act as a NAT gateway between an external host connected through its Ethernet port, and the Android device's internal WiFi connection (not its cellular connection).
I have tried searching for a simple NAT daemon available for any operating system, just for kicks. It turns out that such a solution is nothing more than a pipe dream, considering they would require unportable kernel modules.
I have noticed some Android software out there, such as EasyTether, that claim they support NAT. And, this is apparently even without requiring a rooted system. So, it must be possible to implement based off some solution.
I even recall one such software stating that it had used a Java NAT solution. I could not find anything like this made in Java. Running Java apps on Android IS a possibility.
So, does anyone have any input as to how a NAT solution might be implemented? TIA.