How
DHCP works:
- When a client computer is started, it broadcasts a message requesting a DHCP server. This request includes the hardware address of the requesting client.
- Any DHCP server receiving the broadcast will send out its own broadcast message to the client offering an IP address for a set period of time, known as the lease period.
- The client selects one of the offers received. Normally, it looks for the longest lease period.
- The client broadcasts that it has selected an offered leased IP address and identifies the selected server.
- All non-selected servers return their offered IP addresses back to the pool of available addresses.
- The selected DHCP server gives an acknowledgement that includes the IP address, subnet mask, default gateway, DNS server and the lease period. The information broadcast is configurable. (Note from Zorin: a DHCP server's reply to a client is a unicast packet.)
The process is completed, and the client has access to the network. At this point, the user normally logs on.