Apparently, the latest auto update patch KB951748 (for all versions of Windows) cuts connectivity for all users with ZoneAlarm set to ‘high’ security for the internet zone.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/68076/zonealarm-uhoh.txt
Source: https://packetstormsecurity.com/files/68076/zonealarm-uhoh.txt.html