You have four testing devices that are configured with static IP addresses as shown in...

The DHCP planning and configuration section in Administering Windows Server Hybrid Core Infrastructure states: “Use exclusion ranges to prevent the DHCP Server from leasing specific addresses that are in use by statically assigned hosts.” Reservations are intended for DHCP clients that must always receive the same IP from the scope; they do not apply to devices configured with static IPs and would add unnecessary administration. Because the four test devices are statically addressed and are powered on only monthly, the simplest way to ensure the DHCP server never leases their addresses is to exclude those exact IP addresses from the scope. Scope options and policies do not reserve or block individual addresses from lease assignment. Therefore, to prevent conflicts with minimal effort, configure exclusion entries for 192.168.16.242–245 in the relevant scope.