If a client does not have an IP address and it need to use DHCP, it will assign 0.0.0.0 as the source IP and 255.255.255.255 as the destination IP address until the DHCP server returns the appropriate LAN address.
Block 0.0.0.0 and/or 255.255.255.255 and you can stop the client from getting an assigned DHCP address.
Throw in LAPS for additional painful excitement.