DHCP Operation

Posted: 23rd July 2020 by ccna7guru in ITN

The DHCP Process:

•When an IPv4, DHCP-configured device boots up or connects to the network, the client broadcasts a DHCP discover (DHCPDISCOVER) message to identify any available DHCP servers on the network.

•A DHCP server replies with a DHCP offer (DHCPOFFER) message, which offers a lease to the client. (If a client receives more than one offer due to multiple DHCP servers on the network, it must choose one.)

•The client sends a DHCP request (DHCPREQUEST) message that identifies the explicit server and lease offer that the client is accepting. 

•The server then returns a DHCP acknowledgment (DHCPACK) message that acknowledges to the client that the lease has been finalized.

• If the offer is no longer valid, then the selected server responds with a DHCP negative acknowledgment (DHCPNAK) message and the process must begin with a new DHCPDISCOVER message.

Note: DHCPv6 has a set of messages that is similar to those for DHCPv4. The DHCPv6 messages are SOLICIT, ADVERTISE, INFORMATION REQUEST, and REPLY.