What is DHCP and How DHCP Works

The Dynamic Host Configuration Protocol ( DHCP ) is a standardized network protocol used on Internet Protocol (IP) networks. The DHCP is controlled by a DHCP server that dynamically distributes network configuration parameters, such as IP addresses, for interfaces and services. A router or a residential gateway can be enabled to act as a DHCP server. A DHCP server enables computers to request IP addresses and networking parameters automatically, reducing the need for   a user to configure these settings manually. In the absence of a DHCP server, each computer or other device on the network needs to be manually assigned to an IP address.

DHCP operations fall into four phases:

  

DHCP server discovery, DHCP IP lease offer, DHCP IP lease request, and DHCP IP lease acknowledgement. These stages are often abbreviated as DORA for discovery, offer, request, and acknowledgement.

  

o    Its uses UDP datagram.

o    Client and server use broadcast to communicate until client has assigned address.

o    Client broadcast to locate available servers.

o    Server sends to client response to DHCPDISCOVER with offer of configuration parameters.

o    Client broadcasts to server requesting offered parameters from on server.

o    Client sends to server to release assigned address.

o    Client sends to server indicating IP Address Conflict.

o    Server sends to client refusing request for configuration parameters.

o    server send to client with configuration parameters, including address.