Internet Connection Sharing and Firewall

I'm trying to set up internet connection sharing between my two computers, but I'm having big difficulties. I'm using Kerio Personal Firewall, and when the firewall is on, the other computer looks as if it is connecting, and gets the IP of the site, so there is obviously some connection (for example, if I typed in google.com, it would then say 'Connecting to' and then googles IP, if it wasnt working at all, it wouldnt get the IP) but it never gets the page, and just brings up the page cannot be dispalyed error. However, when I turn off the firewall, it works fine. I'm wondering what rules I should put in Kerio to set up internet connection sharing to work properly?

Thankyou

 

From the Kerio Personal Firewall manual:

"Personal Firewall is designed for protecting a single computer. However, a great amount of packets pass the internet gateway (router) that are not addressed to this computer. In order not to be forced to define complex packet filters, Personal Firewall can be switched to a special mode designed for Internet gateways. This can be done in the Firewall Configuration window (after pressing the Advanced button) on the Miscellaneous tab by enabling the option 'Is running on Internet gateway'. "