I have used ZoneAlarm Internet Security (Extreme Security since it became available) on 3 Windows PC's for many years.
I have allways used Windows Internet Connection Sharing on the computer that was connected to the internet. Now I installed Windows on a new Harddisk on the internet connected PC.
I installed ZoneAlarm Extreme Security 10.1.079.000. Now Internet Connection Sharing is not working.
If I lower Security in the public Zone to medium, ICS is working, but I don't want to do that.