The client-server protocol DHCP is used in order to dynamically assign
IP addresses to hosts. When a new client-PC arrives in a network, it needs
network information (e.g. an IP address) that is provided by the DHCP-Server.
In summer 2006 the football world champion ship took place in Germany,
and thatís the reason for this analogy: IP address configuration is described
by the example of a new player coming to a football team and requesting
a number for his jersey.
1. DHCP-DISCOVER: In order to get an IP address the new
client PC first broadcasts a DHCP-DISCOVER message into the network. With
this message it is searching for the DHCP-Server.
2. DHCP-OFFER: The DHCP-Server answers to the request
by broadcasting a DHCP-OFFER message including the IP address and subnet
mask he can provide for the client.
3. DHCP-REQUEST: In the next step the new client will
choose among the server offers (if there are more than one) and responds
to its selected offer by boadcasting a DHCP-REQUEST message.
4. DHCP-ACK: The final step is that the DHCP-Server sends
back a DHCP-ACKNOWLEDGMENT message and confirms the offered IP address.
The client is now able to use this address for the lease period.