Suppose in DHCP server running network(assigning ip addresses automatically), you connect a Laptop in the same n/w, now how the DHCP is going to assign a IP add. to it and how it will came to know that there's one new machine added ?

when a new machine is connected to network. one the machine is started, it sends a broadcast asking for a IP address, when the DHCP server listens to the broad cast, it send a IP address from the scope .

the process is know as DORA

discover-- discovery dhcp server (client)
offer----- sends and IP address (server)
respond--- i have received the IP address (client)
acknowledge--- the lease period to renew the ip address( server)

ipconfig/relese
ipconfig/renew