Dynamic Host Configuration Protocol

 What is DHCP server and how does it works?

• The Dynamic Host Configuration Protocol (DHCP) is a network management protocol that assigns an IP address to any device or node on a network in order for them to interact using IP (Internet Protocol). 
• These setups are automated and managed centrally using DHCP. There's no need to give IP addresses to new devices manually. As a result, to connect to a DHCP-based network, no user setup is required.
• DHCP is a protocol that may be used on both small and big corporate networks. Most routers and networking devices utilize DHCP as the default protocol. 
• RFC (Request for comments) 2131 is another name for DHCP.

Working of DHCP Server:

• All nodes or devices that are added or removed from the network are managed via DHCP.
• DHCP keeps the host's unique IP address when it connects to a DHCP server.
• When a client/node/device that is set to function with DHCP connects to a network, it makes a request to the DHCP server. The server responds by giving the client/node/device an IP address.
• On the node or device, DHCP is also used to set the right subnet mask, default gateway, and DNS server information.
• Many versions of DCHP are available for usage with IPV4 (Internet Protocol Version 4) and IPV6 (Internet Protocol Version 6). (Internet Protocol Version 6).

DHCP Server

• DHCP is a protocol that dynamically assigns IP addresses to DHCP clients/nodes and allocates TCP/IP configuration information to DHCP clients. It operates at the application layer of the TCP/IP protocol stack. 
• Subnet mask information, default gateway, IP addresses, and domain name system addresses are all included in the data.
• DHCP is a client-server protocol in which servers control a pool of unique IP addresses as well as client configuration settings and allocate addresses from those pools.

The following is how the DHCP lease works:

• First and foremost, a client (network device) must have internet access.
• IP addresses are requested by DHCP clients. Typically, the client sends out a query for this data.
• The DHCP server replies to the client's request by supplying the IP server address as well as other configuration details. This configuration information also provides the time period for which the allocation is valid, referred to as a lease.
• A DHCP client requests the same parameters while renewing an assignment, yet the DHCP server may issue a different IP address. This is determined by the administrator's policy.

Components of DHCP:

It's critical to grasp all of the components of DHCP while working with it. The following is a list of the components:

1. DHCP Server: A DHCP server is a networked device that contains IP addresses and related configuration information and runs the DCHP service. This is usually a server or a router, although anything that operates as a host, such as an SD-WAN device, can be used.
2. DHCP client: The endpoint that receives configuration information from a DHCP server is known as a DHCP client. This can be any device that requires network access, such as a computer, laptop, IoT endpoint, or anything else. By default, most devices are set up to receive DHCP information.
3. IP address pool: The IP address pool is the set of addresses that DHCP clients have access to. IP addresses are usually assigned in the order of lowest to greatest priority.
4. Subnet: A subnet is a portion of an IP network that has been partitioned. Subnets are used to keep networks under control.
5. Lease: A DHCP client's IP address information is held for a certain period of time. The client must renew the lease when it expires.
6. DHCP relay: A host or router that listens for client communications on a network and relays them to a specified server. After that, the server sends replies to the relay agent, who forwards them to the client. Instead of having a server on each subnet, DHCP relay may be used to centralize DHCP servers.

DHCP has the following advantages:

• Centralized IP configuration: DHCP IP configuration information can be maintained in a single location, allowing an administrator to handle all IP address configuration information from a single location.
• Configuration procedure: DHCP simplifies the host configuration procedure, removing the need to manually configure each host. When TCP/IP (Transmission control protocol/Internet protocol) is first introduced or when improvements to the IP infrastructure are needed.
• IP host configuration: DHCP guarantees that DHCP clients get correct and timely IP configuration parameters such as IP address, subnet mask, default gateway, IP address of DND server, and so on.
• Flexibility and scalability: DHCP provides the administrator more flexibility by allowing him or her to quickly alter IP configurations as the infrastructure evolves.