Hi, How to configure DHCP server (W2K3) on the private network so it will be assigning the IPs only to known machines. Do I have to use it reservation option so it won't be assigning IPs to unknown clients? Basically I would like to prevent access to the network and limit only to known clients. What if someone manually assign static IP (from the range of the network not even from the DHCP scope). How to prevent him from accessing the network.