Hi, I need some advice.

I have a PC with Knoppix that works as Proxy server and Internet Direct Connection for our Local Network users. How is that, I have 2 eth card, one with a Public IP and another with a Private IP. I configured the iptables to make nat and block some services, also activate the proxy server, and for the clients works excellent. In my laptop I have Mozilla with direct conection to internet and Internet Explorer with proxy server configured, and both works fine.
After a few hours of working, you could't get access with any browser. If you do a ping test with IP or URL it works, even the Outlook works, but if I use a browser (let's say Internet Explorer, Mozilla or Firefox) you can't access. In the Knoppix server still works the access. Only doesn't work for the clients.
I have to turn off and turn on again the proxy service to start working again.

Someone has an idea??????

Sorry for my bad English.

mcamacho.