Create an interface address pool for IP address allocation to clients on the same network segment as the DHCP server's interface, or create a global address pool for IP address allocation to all clients connected to the DHCP server.
The sum of the number of IP addresses being in use and that of expired IP addresses equals the number of DHCP clients. When the sum of the number of IP addresses being in use and that of expired IP addresses reaches the maximum of DHCP client specification, the device can automatically release some of the expired IP addresses to reduce the memory usage.