You are the network manager for a computer training center that allows students to bring their own laptops to class for learning and taking notes. Students need access to the Internet, so you have configured your network's DHCP server to issue IP addresses automatically. Which DHCP option should you modify to make sure you are not wasting addresses used by students who have left for the day?

Answer: Lease Time

Explanation:

Once a PC user turns on his device, the DHCP client within it will issue a DHCP discover command, a broacast message that will be answered by the network DHCP server.

The second step will be a DHCP request by the client, which will be answered by the server, giving the requesting user, an IP address, from the pool of IP addresses available.

If this assignment were permanent, at the moment that the user removed the PC from the network, he would take the IP address with him, wasting it in this way.

In order to avoid it, the DHCP server actually leases the IP address, giving a programmable lease time to the requesting machine.

If the DHCP client doesn't ask for a renewal before that the lease time expires, the DHCP server will get back this IP address, adding it to the IP addresses pool again.

If, for instance, lease time is fixed to one hour, if someone leaves before that time, the IP address will be available again one hour after having being leased.