The first step in a successful Dynamic Host Configuration Protocol (DHCP) lease process occurs when a DHCP client sends a DHCPDISCOVER broadcast.

A DHCPDISCOVER packet is used to locate a DHCP server. If no DHCP server is available, the DHCP client will not be able to dynamically receive IP configuration information and, thus, will not be able to communicate on the network.

The second step in a successful DHCP lease process occurs when one or more DHCP servers send a DHCPOFFER unicast to the DHCP client. A DHCPOFFER packet contains IP configuration information, such as the IP address, subnet mask, default gateway, and Domain Name System (DNS) server addresses that a client should use.

The third step in a successful DHCP lease process occurs when the DHCP client sends a DHCPREQUEST broadcast. A DHCPREQUEST packet formally requests the IP address fromthe DHCP server. The DHCPREQUEST packet is broadcast to the entire network rather than unicast to the specific DHCP server so that the other DHCP servers can reallocate the IP addresses they offered to the DHCP client.

The fourth step in a successful DHCP lease process occurs when the DHCP server sends a DHCPACK unicast to the DHCP client. A DHCPACK packet confirms that the IP address hasbeen officially assigned to the client for the duration of the lease.

Some packets are sent only during an unsuccessful DHCP lease process. A DHCPDECLINE packet is the opposite of a DHCPREQUEST packet. A DHCPDECLINE packet is a broadcast packet that a DHCP client sends to formally reject a DHCPOFFER from a DHCP server. A DHCP client usually sends this kind of packet when the IP configuration is not valid for the client.

A DHCPNAK packet is the opposite of a DHCPACK packet. A DHCPNAK packet is a broadcast packet sent by a DHCP server to inform a DHCP client that the IP address in the DHCPREQUEST is no longer valid for the client to use. A DHCP server usually sends this kind of packet when the DHCP client is slow to respond to the DHCP server.