Pardon me if I'm asking the wrong question. But I am a newbie in networking and I'm not sure what direction to go on this.

I have just setup an Ubuntu Desktop. I am planning to convert it to a network server without losing the GUI interface (again, I'm a newbie) and use it to manage and monitor user access to a network with a small number of network terminals all running on Windows. My purpose is to use the new server to filter sites accessed by each terminals, monitor sites being visited by employees and grant access to both group and user-specific folders based on their IP address.

Is this possible?

1. What server software do I need to install?
2. How do I structure the hardware? (I have a router, a hub, the Ubuntu server and the network terminals)
3. How do I assign privileges to users and monitor them at the same time?

Thank you in advance for your replies.