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DHCP - Dynamic Host Configuration Protocol

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.

Have fun with the football analogy!