android.clients.google.com app-measurement.com clients1.google.com clients2.google.com clients3.google.com clients4.google.com clients5.google.com clients6.google.com connectivitycheck.android.com connectivitycheck.gstatic.com dl.google.com googleapis.l.google.com google.com www.google.com .sites.google.com .www3.l.google.com
These domains are checked by the operating systems when connecting via wifi, and if they do not get the response they expect, they may try to open a WiFi login page or similar as they believe they are located behind a captive portal.
android.clients.google.com clients3.google.com connectivitycheck.android.com connectivitycheck.gstatic.com
googleapis.l.google.com
dl.google.com # to update.
clients2.google.com clients4.google.com
To load google maps data (photos, maps, locations, location info, etc) until reaching a timeout (15-20 seconds):
app-measurement.com
android.clients.google.com
Might also need:
clients1.google.com clients2.google.com clients3.google.com clients4.google.com clients5.google.com clients6.google.com
clients2.google.com clients4.google.com
google.com www.google.com .sites.google.com .www3.l.google.com # CNAME for (sites.google.com)