iphoneNetworktethering
I have this program on my mac that streams my gps location over the private network.
When on the road, my program needs an internet connection as well as the gps data, so I need to pair to my iphone to get internet. After doing this, however, my program can't determine my iphone's IP address so I can't get the location data.
Does my iphone have an IP address when it's the "router" effectively, via personal hotspot??
If you plug any cellular enabled iOS device with Personal Hotspot turned on to a Mac via USB, the Mac will automatically open a network connection using the Personal Hotspot.
So yes, your Macbook Air will be the 1 connection you see.
The second part of your question is a little trickier and the answer is both complex and confusing but I will try to explain as best I can.
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Based on older knowledge with other multiple interface *nix systems is that it will be a complete toss up as to which connection your Mac will use since both active connections could possible provide the same route to the destination for any network query.
I have even seen, on both Windows and Unix networks, traffic coming in on one network connection and going out on another, which rarely works well.
To get round this, in the Network panel you could disable the "iPad USB" in your default location, but then set up a new location where your "iPad USB" is not disabled.
Finally, the order of your devices should mean that if your wifi is above the iPad USB device in your list when both are enabled, it will get priority over the hotspot, but there are still caveats and this could still use cellular data, but of a lesser amount.
You cannot use your Wi-Fi connection for Internet connectivity while other devices are using Wi-Fi for Personal Hotspot. You can share only a cellular data connection; you cannot share a Wi-Fi connection.
As seen here: http://support.apple.com/kb/ht4517
Best Answer
The answer is
172.20.10.1Found this out by checking out the gps2ip settings and saw there were some provisions for using a personal hotspot and it told me there. You have to tell gps2ip to pipe over the hotspot from within the app to make it work regardless.