DHCP

 DHCP stands for Dynamic Host Configuration Protocol. It is a network protocol used to automatically assign IP addresses and other network configuration parameters to devices on a network. DHCP simplifies the process of assigning IP addresses and eliminates the need to manually configure network settings on individual devices.

This is how DHCP works:

 DHCP server: A DHCP server is a network device (often a router or dedicated DHCP server) that is responsible for assigning IP addresses and other configuration parameters. It has a pool of available IP addresses that it can assign to devices on the network.

 DHCP discovery: When a device (called a DHCP client) connects to a network, it sends a DHCP discovery message as a broadcast request to find a DHCP server. This message is usually sent when a unit is commissioned or connects to a new network.

 DHCP Offer: After receiving the DHCP Discover message, the DHCP servers respond with a DHCP Offer message. The offer contains an available IP address from the server's pool as well as other configuration parameters such as subnet mask, default gateway, DNS server addresses and lease duration.

 DHCP request: The client receives several DHCP offer messages (if available) and selects one of the offers. It sends a DHCP request message to the selected DHCP server, confirming acceptance of the offered IP address and other parameters.

 DHCP Confirmation: The DHCP server responds to the client's request with a DHCP confirmation message, confirming the assignment of the requested IP address and indicating the lease period. The client can now use the assigned IP address and apply the provided network configuration.

 Lease renewal: DHCP leases are usually time-limited and allow the client to use the assigned IP address for a specified period of time. Before the contract expires, the client can request a contract renewal by sending a DHCP request to the DHCP server. If the server approves the renewal, it sends a DHCP confirmation message with an updated lease duration.

By using DHCP, network administrators can efficiently manage the assignment and configuration of IP addresses on a network. Conflicts that can arise from manually assigning IP addresses are avoided and adding new devices to the network is simplified. DHCP also supports centralised management and enables easier changes to the network configuration by changing the DHCP server settings instead of updating each client device individually.