How does Android determine if it has an Internet connection?
When the data indicator is orange (on Kit kat ; grey on older versions), this means that the device is unable to receive a response from GCM (Google Cloud Messaging, the framework that handles push notifications). This traffic is sent through ports 5228, 5229, and 5230. If the AP is blocking or interfering with traffic on those ports, push notifications won't work and the data indicator will be orange. Manual refreshes and other Internet traffic will still work fine if the ports used for those transmissions (80, 443, etc.) are not blocked.