[Android Central Question]

I use several tablets (Lenovo Tab 7 Essential) at work on the work WiFi, but my tablets neither see nor download Android OS updates, probably because the site they are looking for is blocked by my work IT department. The Google Play store DOES download and update my apps. What is the server address / url that the tablet polls for OS updates? I figure if I can convince my office to "whitelist" that server, I can have my tablets do updates at work, rather than having to take them home, periodically.