Internet routing between wlan0 and ppp0?

Question

I am developing an iPad application. In my application users can move, rotate and scale images. I've noticed that when I add a 3d shadowed border to the images, it makes them incredibly heavy and unresponsive. I add the border using this code:

self.layer.MasksToBounds = false;
self.layer.ShadowColor = [[UIColor alloc] initWithRed:0 green:0 blue:0 alpha:0.5].CGColor;
self.layer.ShadowOpacity = 1.0f;
self.layer.ShadowOffset = CGSizeMake(0, 2.5f);

Why does this happen? What ways do I have to solve this?

Solution

You can refer to this wiki that explain a very simple and complete way of acheving what you want with iptables, This explain how to Nat your wifi interface behind you ppo interface.

Edit 1: You can also make your two interface working as a bridge aka switch but it would probably be a bit more tricky, some info about that here

Comments

[jamesmortensen]

Hi Lukas, one suggestion to make your answer stand out more is to add more information about what that does. Others who visit this question and answer would potentially learn more from your answer and upvote! Good luck! :)

[Ugh.]

Thank you. I used some iptables rules that where supposed to work, but they did not. It turned out later that my problem was not the iptables rules, but that I was using the same subnet for both wlan0 and ppp0. Using different subnets solved the problem.