We have a very large wifi network at Stack Exchange, and the primary guest network is tightly locked down. Our firewall rules permit essentially just http/https and vpn connections. When our Android phones connect to the wifi, they show good coverage but the WiFi icon never turns from grey to blue.
What is the Android phone checking to make the grey/blue wifi icon decision in JB 4.2.2?
After probing the firewall logs, it appears that the grey/blue icon is triggered depending on whether or not your device has access to Google Play. In our case, I had to open tcp-udp port 5228 (as per http://support.google.com/googleplay/bin/answer.py?hl=en&answer=2651367) and after turning wifi off and back on again, the icon became blue.
I can't confirm whether http/https is also part of the equation; we already had that open so it's possible if one is running into this issue even after opening tcp-udp 5228, that http/https may also be required.
