DHCP LEASE PROCESS

1. Discover: The host will initially send a broadcast in an attempt to discover a DHCP server on the network.
2. Offer: The DHCP server will 'see' the workstation looking for the DHCP service and respond with an 'offer', which is an IP address.
3. Request: The client will receive the 'offer' and, in most cases, will accept it. This means it sends an 'official request' for the same IP address offered previously by the server.
4. Accept: The DHCP server will complete the transaction by sending an 'accept' message and marking the particular IP address for the specific host.

DHCP SERVER- Dynamic host configuration protocol is used to automatically assign TCP/IP addresses to clients along with the correct subnet mask, default gateway, and DNS server.
169.254.0.0 -169.254.255.255-APIPA Address

BOOTP- short for Bootstrap Protocol is a UDP network protocol used by a network client to obtain its IP address automatically. This is usually done during the bootstrap process when a computer is starting up. The BOOTP servers assign the IP address from a pool of addresses to each client.

BOOTP/DHCP differencesThere are significant differences in the way in which BOOTP and DHCP perform host configuration. The following table compares and contrasts the features of the two protocols that vary.

BOOTP DHCP Designed prior to DHCP. Designed after BOOTP.Intended to configure diskless workstations with limited boot capabilities. Intended to configure frequently relocated networked computers (such as portables) that have local hard drives and full boot capabilities.Dynamic BOOTP has default 30-day expiration on IP address leases. DHCP has default eight-day expiration on IP address leases.Supports a limited number of client configuration parameters called vendor extensions. Supports a larger and extensible set of client configuration parameters called options.Describes a two-phase bootstrap configuration process, as follows:• Clients contact BOOTP servers to perform address determination and boot file name selection.• Clients contact Trivial File Transfer Protocol (TFTP) servers to perform file transfer of their boot image. Describes a single-phase boot configuration process whereby a DHCP client negotiates with a DHCP server to determine its IP address and obtain any other initial configuration details it needs for network operation.BOOTP clients do not rebind or renew configuration with the BOOTP server except when the system restarts. DHCP clients do not require a system restart to rebind or renew configuration with the DHCP server. Instead, clients automatically enter a rebinding state at set timed intervals to renew their leased address allocation with the DHCP server. This process occurs in the background and is transparent to the user.

ARP (Address Resolution Protocol)Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP address) to a physical machine address.

RARP (Reverse Address Resolution Protocol)Address Resolution Protocol (ARP) is a protocol for mapping a physical machine address to Internet Protocol address (IP address).

DHCP Relay AgentThe DHCP Relay Agent component is a Bootstrap Protocol (BOOTP) relay agent that relays Dynamic Host Configuration Protocol (DHCP) messages between DHCP clients and DHCP servers on different IP networks. The DHCP Relay Agent is compliant with RFC 1542. You cannot use the DHCP Relay Agent component on a computer running the DHCP service. BOOTP is a host configuration protocol developed before DHCP that was designed to configure diskless workstations with limited boot capabilities