The problem is very weird and i couldn't manage to find anything about it on the internet so it makes me think that maybe it is case specific. Anyways, it goes as following:
I have a HP Pavilion g6 (very poorly supported notebook in my opinion) with the following adapter :
02:00.0 Network controller: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter (rev 01)
I have an iPhone 4S. When my Ubuntu pc is not connected to the wireless network that I have internet on the iPhone is working just as it should. When using Windows (same pc, dual boot) internet on the iPhone is also working. But when I'm using Ubuntu internet on the phone is not working. The phone is connected to the network but no internet, sometimes it is not even connnected to the network and has hard time connecting. As soon as I disconnect my laptop from the network iPhone works again.
I'm posting it here because I think this is Ubuntu related... Hope someone comes up with an answer. Cheers