What is DHCP?

Dynamic Host Configuration Protocol (DHCP) is a protocol that is used to automatically assign IP addresses and network configuration parameters to devices on a network.  When a device connects to a network, it needs to be assigned an IP address that is within that network to communicate on the network. This is where DHCP comes in. It provides the device with an IP address, subnet mask, default gateway, DNS server addresses and other network  configuration information. 

Here is how it works:

When a device(also known as a DHCP client) connects to a network, it sends a  broadcast DHCP discovery message to locate a DHCP server within the local network. 

The DHCP server receives the message and responds with a DHCP offer. This offer includes an available IP address that can be assigned to the device, subnet mask, default gateway, DNS server addresses and other network configuration information.

The DHCP client receives one or more DHCP offers and selects one of them. It sends what is known as a DHCP request to the DHCP server that provided the offer, indicating that it’s accepting the DHCP offer provided. 

The DHCP server receives the request and sends a DHCP acknowledgement message to confirm the IP address assignment and provides additional network configuration  details.

The DHCP client receives the acknowledgement and configures its network interface with the provided information from the DHCP server. At this stage, the DHCP client or device is ready to communicate on the network.

When a DHCP client is assigned an IP address, it is leasing the assigned IP address for a specific period. This period is usually controlled by the DHCP server.  As the lease expiration approaches, the client needs to send a DHCP request to the DHCP server to renew the lease. In most cases, the lease is renewed and the DHCP client retains the original IP address. 

When a client disconnects from the network or no longer needs the IP address, it sends a DHCP release message to the DHCP. This informs the server that the IP address is no longer in use and  it can reassign the IP address when needed. 

DHCP servers play an important role on a network toward efficient client management on a network. The DHCP server manages a pool of available IP addresses and dynamically assigns them to devices as they join the network.  It allows for easy management, allocation, and configuration of devices on a network avoiding IP address conflicts. The configuration details provided by the DHCP server vary from server to server depending on the network setup, and DHCP server configuration.