I have written an App which extracts data, over WiFi, from an instrument that creates its own WiFi Hotspot. The instrument provides no internet connection. The iPad version of this App is connects fine and is assigned an IP address by DHCP server running on the RN171 wifi module.

However in the case of the iPhone I am forced to manually assign an IP address for the iPhone, the mask and the gateway. Only then is the connection successful.

Anyone know why the iPhone won't talk DHCP to a WiFi module not connected to the internet?