I had the same problem upgrading to the new iPad Air, and hence from iOS6 to 7.
I use an Apple script on my Mac Mini to create an ad-hoc network (with a static IP) on startup, so that I can connect to it from my iPad and use that as a screen (and as a controller for my music software on the Mini).
After the upgrade, trying to connect to my usual ad-hoc network brought up the 'not connected to the internet' alert and, though it seemed to be connected (there was a checkmark in front of the network name) the apps I use did not work. Also, there was no signal-strength icon on my iPad, which used to be there in my old setup.
The following procedure seems to have solved the issue for me. And though reading these posts it appears as if different people are experiencing different issues, I thought posting my solution might be useful to some.
On the Mac Mini side I did the following:
- created an ad hoc network with different properties than before, that is: new name, manually configured ip address in a different ip-range than before.
So, for example, if before, I used to have a network named Blahnet with IP address 192.168.100.1 (subnetmask 255.255.255.0) I now had Bluhnet with IP 192.168.99.1 (subnetmask 255.255.255.0). As far as I can tell, the channel number and password settings do not make a difference.
On the iPad side I did the following
- The new network shows up under 'devices'. Instead of connecting to it right away, I clicked on the question mark button to the right of the network name.
- In the IP-address section, I clicked the Static tab, and entered the info there, with the IP itself being in the same range as on the Mini, and the Router and DNS set to the IP I entered on the Mini.
So, in the above example, that would be: IP 192.168.99.4; Subnetmask 255.255.255.0; Router 192.168.99.1; DNS 192.168.99.1.
- Finally, click the Connect to Network link at the top, enter the password, and that's it.
Doing this, the signal strength icon does appear on the iPad, and the music control apps work.
Good to know: the static IP profile is tied to the specific network, so after setting it up like this the first time, I can connect to the same network the next time by simply clicking it (without having to set up the static IP manually each time). Similarly, when connecting to my other, usual wifi networks at home or at work, the iPad automatically uses DHCP.
My guess is that my network profile was copied from the old iPad to the new (and from iOS 6 to 7) but the ad hoc connection works a bit differently now, so the ad hoc connection failed. Unfortunately, there is no indication on the iPad that something is wrong, leaving you to guess at what it might be.
Good luck in trying to find a solution.
Cheers