My iPhone 4 will tether nicely via USB with either my laptop or desktop machines. Also, if I enable 'Internet Sharing' on the machine that the iPhone is tethered to, and connect that machine directly to the other via Ethernet (computer to computer, no switch/router in between), the second machine will happily share the internet connection from the first as well. All good so far. But when I insert a router between the two computers (Billion ADSL router, obviously not using the ADSL part) the second computer can no longer access the internet connection that is being provided by the tethered iPhone on the first computer. Can anyone confirm that Internet Sharing only works directly computer-to-computer, and not with a router/switch in the middle? I need to keep the router in the system as I have a networked printer - I was hoping to use the iPhone in place of router-based ADSL link and thus share it between 2-3 computers on the LAN. Is this definitely not possible or is there a setting/issue that I'm missing? Any help greatly appreciated!