yannaing

Dear,
I have a small network, there is 20 client computers and one server(Microsoft server 2003). I give the Internet connection to the Clients computer through the server. I had installed the ISA software on the server(2003). Sometimes the client computers don't get the Application From the Internet or don't get the internet connection through the server. So i restart the Microsoft Firewall Service on the server. After I had done it, the client computers reget the internet connection or application from the internet.
I want the client computers to always get the internet connection through the server without restarting the Microsoft Firewall Services on the server.
Please help me!!!