Default nexter - quadrocopter piloted by a nexus s

I have built a quadrocopter with all avoinics controlled by an android app. The app streams 50 commands per sec to the four motors with the power. The gyros, accelerometers and magnetometers is read by the app, fed though some mathematics and three PID regulators to balance the machine. The garbage collector makes it jump alittle from time to time, but it works!

Now to my problem. I want the phone to act as a wifi access point presenting itself with a web page with all details for connecting to it. The manual control is through an app running on my current Nexus 5 connecting to the nexus s ap.

With the factory reset nexus s, I can start the portable hotspot, and conect to the phone from anywhere. But I cant connect to any server running on it.
I assume that the phone have ip filtering rules that forward all incoming packages to the 3G interface to be delivered to the internet through the telecom net.
I have rooted the phone and installed droidwall and I can run the iptables command.
I have installed a simple web server that I can reach at when the phone is conected to my home ap.
But when the hotspot is running the web server says it can be reached at and android settings/my phone says the ip no is undefined

So I need some advice on how to tweak android to let packets to its portable ap reach my web server. The phone needs an ip no, and some iptable rules probably.