In order for users on your network to access Google Drive and Google Docs editors, your firewall rules should connect to the following hosts and ports. Otherwise, users may be blocked or denied access from these services.
For the following hosts, [N] means any single decimal digit and * means any string not containing a period.
Oauth server
- accounts.google.com:443/HTTPS
API stuff
- apis.google.com:443/HTTPS
- *.clients[N].google.com:443/HTTPS
- *.googleapis.com:443/HTTPS
- script.google.com:443/HTTPS
Other
- www.google.com:443/HTTPS
- googledrive.com:443/HTTPS
- drive.google.com:443/HTTPS
- *.drive.google.com:443/HTTPS
- docs.google.com:443/HTTPS
- *.docs.google.com:443/HTTPS
- *.c.docs.google.com:443/HTTPS
- sheets.google.com:443/HTTPS
- slides.google.com:443/HTTPS
- talk.google.com:5222/XMPP (needed only for Backup and Sync or the legacy - version, Drive for Mac/PC)
- takeout.google.com:443/HTTPS
- gg.google.com:443/HTTPS
- ssl.google-analytics.com:443/HTTPS
- video.google.com:443/HTTPS
- s.ytimg.com:443/HTTPS
- *.googleusercontent.com:443/HTTPS
- *.gstatic.com:443/HTTPS
- lh[N].google.com:443/HTTPS
- [N].client-channel.google.com:443/HTTPS
- clients[N].google.com:443/HTTPS
Ripped from Google Drive firewall and proxy settings
Some of theses are for google drive the web application and others are for google drive api, sheets api and the oauth servers. I could probably wittle it down a little but wasnt sure if you wanted that. It may be best that they just open most of them and go from there.