what is DHCP protocol ? | Dynamic Host Configuration Protocol | DCHP | CCNA 200-301 2023

DCHP One of the most commonly used protocols in a TCP/IP network. DHCP, is a network management protocol used to dynamically assign an IP address to any device, on a network.
DHCP, automates and centrally manages, these configurations rather than requiring network administrators to manually assign IP addresses to all network devices.
DHCP assigns new IP addresses in each location when devices are moved from place to place like, with a tablet computer-to a coffee shop, or back at the office-the user’s device can connect to another wireless LAN, use DHCP to lease a new IP address in that LAN, and begin working on the new network.
Without DHCP, the user ask for information about the local network and configure settings manually, if you setting IP manually, with more than a few users making mistakes.
Every device on a network must have a unique, unicast IP address to access the network and its resources.
It is important to know why we use DHCP?
DHCP minimizes configuration errors, such as typographical errors and also prevent address conflicts, between two computers.
Reduce network administration by Centralized and automated configuration.
Also efficient handling of IP address changes for clients, such as those for portable devices that move to different locations on a wireless network.
Using a DHCP relay agent, which eliminates the need for a DHCP server on every subnet.
Also The DHCP server stores the configuration information in a database,,,,,,,,,,,,,,,,,, like:
• Valid TCP/IP configuration for all clients on the network.
• Valid IP addresses, as well as excluded addresses.
• Reserved IP addresses associated with particular DHCP clients, This allows single IP address to a single DHCP client.
• The lease duration, or the length of time for which the IP address can be used before a lease renewal is required.
DHCP server stores these configurations information in its database.
DHCPv4 allows a host to obtain an IP address dynamically when it connects to the network.
A client typically broadcasts a query message for this information immediately after booting up. The DHCP server responds to the client request by providing IP configuration information from a configured range of addresses, called a pool, which previously specified by a network administrator. This includes a specific IP address, and duration of the lease.
For example, the (DHCP process to lease an IP address) uses this four messages, between the client and server.
When a DHCP-configured device connects to the network, the client broadcasts a DHCPDISCOVER packet to identify any available DHCP-servers on the network.
A DHCP server replies with a DHCPOFFER, which is a lease offer message with an assigned IP address, subnet mask, DNS server, and default gateway information, as well as the duration of the lease.
The client can receive multiple DHCPOFFER packets, if the local network has more than one DHCPv4 server.
The client chooses the first offer and broadcasts a DHCPREQUEST packet that identifies the explicit server, and lease offer that it is accepting.
DHCP server, send ACKNOWLEDGEMENT packet to assign the address, subnet mask, default router, and DNS server IP addresses
DHCP is not a routable protocol, nor is it a secure one. DHCP is limited to a specific local area network.
If network administrators want a DHCP server, to provide addressing to multiple subnets on a given network, they must configure DHCP relay services located on interconnecting routers that DHCP requests have to cross.
These agents relay messages between DHCP clients and servers located on different subnets.

[@saidmohammeda1876]

8:57 when the DHCP server responds with a DHCP offer message, it sends the message directly to the requesting client's MAC address as a unicast message, not to the broadcast address. The DHCP offer message is not intended for all devices on the network, but only for the requesting client.

[@user-go3ht9rw1f]

Is dhcp offer message is unicast or broadcast, as it have the senders mac address, it can unicast it to its mac address as its a LAN and its not required ip to communicate