Using DHCP, you can manage each client in your network individually, rather than managing all of the clients as a large group (subnet).
This DHCP setup method allows only the clients identified by the DHCP server to receive IP address and configuration information.
People often think about using DHCP to distribute IP addresses from an address pool to a subnet of clients. Any client that requests DHCP information from the network might receive an IP address from the address pool when you use subnets, unless they are explicitly excluded by the DHCP administrator. However, the DHCP server is also capable of the inverse -- limiting DHCP service to only specific clients.
The DHCP server can limit service at both the individual client level and by the type of client (BOOTP or DHCP). To limit service at the individual client level, you must identify each network client individually in your DHCP configuration. Each client is identified by their client ID (typically their MAC address). Only the clients that are identified in the DHCP configuration will be served an IP address and configuration information from the DHCP server. If a client is not listed in the DHCP configuration, it is refused service by the DHCP server. This method prevents unknown hosts from obtaining an IP address and configuration information from the DHCP server.
If you want even more control over your network clients and the configuration information that they receive, you can set up your DHCP clients to receive a static IP address rather than receiving an IP address from an address pool. If you set up the client to receive a defined IP address, that client should be the only client that can receive that IP address to avoid address overlap. If you use dynamic IP address allocation, the DHCP server will manage IP address assignment for the clients.
On a broader level, the DHCP server can limit service to a client based on the type of client, BOOTP or DHCP. The DHCP server can refuse service to BOOTP clients.