@CybertecOne: My network has 8 departments and i wish to separate them but has still access to one server.
OK. So as cheyenne1212 said, you definately want a layer 3 managed switch, with a simple webGUI or application interface.

This will solve all of the problems. Alternatively, you could put each department on different subnets, and configure the server IP NIC as having 8 different IP addresses, one for each department to access. This is the cheap way of doing it, and it is possible to do, but a s***t load of administration would be needed to get it working. Not to mentioned a couple more NICs on the server for redundancy and load balancing.