DHCP-Dynamic Host Configuration Protocol

DHCP is a network protocol that is used to assign various network parameters to a device. This greatly simplifies administration, since there is no need to assign static network parameters for each device separately. DHCP is a client-server protocol. A client is a device that is configured to use DHCP to request network parameters from a DHCP server. DHCP server maintains a pool of available IP addresses and assignes one of them to the host. A DHCP server can also provide some other parameters, such as:
• subnet mask
• default gateway
• domain name
• DNS server

 

Cisco routers can be used as a DHCP server.

 

DHCP process explained:

 

DHCP client goes through the four step process:

 

1: A DHCP client sends a broadcast packet (DHCP Discover) to discover DHCP servers on the LAN segment.

 

2: The DHCP servers receive the DHCP Discover packet and respond with DHCP Offer packets, offering IP addressing information.

 

3: If the client receives the DHCP Offer packets from multiple DHCP servers,
the first DHCP Offer packet is accepted. The client responds by broadcasting a DHCP Request packet, requesting network parameters from a single server.

 

4: The DHCP server approves the lease with a DHCP Acknowledgement packet. The packet includes the lease duration and other configuration information.