Is there a way in OS X to limit data usage over wifi, and if so, can it be done by wifi network? I want to tether my MacBook to my iPhone, but I am worried about background processes running and eating up my iPhone data allowance. Best option would be to be able to limit what type of services can run based on the wifi connection currently connected. Let my home wifi run wild, but limit things like OS updates, photo stream, etc. while connected to my iPhone hotspot. Thanks!