I access my phone through SSH via a wifi network. When I do not do anything over that connection for about ten minutes, it stops responding and I cannot even ping the phone from my computer. When I disconnect and connect the phone from wifi, it starts to respond again.

What is weirder, when i open the terminal on my phone and ping my computer (or do any other kind of network activity like opening a webpage on the phone), it starts responding again two (without disconnecting and reconnecting wifi). It seems like the network connection goes to some kind of sleep, but I have no idea what caused it. I am using the cssu thumb2 packages and the latest powerkernel, but I do not know if it might be related. Anybody has got any ideas what might be causing it? (I guess I could write a script that would ping my computer once a second and this kept the connection alive, but that is not really a solution to the root cause).