Basics of DHCP

Basics of DHCP

Dynamic Host Configuration Protocol (DHCP) a service provided by a server in which the server allocates the client an IP address upon its request.

DHCP required three components to work

• DHCP Server
• DHCP Client
• DHCP Protocol

Dynamic allocation of IPs carried out by assigning IPs from a predefined scope of addresses and for a specific length of time to all devices in a network.

DHCP server: A device running the DHCP service in a network that holds IP addresses and related configuration information. 

DHCP client: The host/ user that receives configuration information from a DHCP server. This can be a computers and mobile devices that requires connectivity to the network.

IP address pool: The series of addresses that are available to DHCP clients. Addresses are normally handed out serially from lowest to highest.

Lease: The length of time for which a DHCP client holds the IP address information. When a lease expires, the client renews it.

DHCP relay: A router or host that listens for client messages being broadcast on that network and then forwards them to a configured server. The server then sends responses back to the relay agent that passes them along to the client. This can be used to centralize DHCP servers instead of having a server on each subnet.

The DHCP protocol: It enables host systems/clients in a TCP/IP network to be configured automatically for the network during the system booting.

Benefits

• Reduced IP Conflict
• Systematic IP Address Management
• Enables centralized client server architecture
• As the DHCP server uses multithreading to processes of many client requests simultaneously, it supports large network operation. 

In computer science, multithreading is the capability of a central processing unit (CPU) to run multiple threads of program execution concurrently.

Cons

• As DHCP server has no secure mechanism for authentication of the client, it can gain unauthorized access to IP addresses by presenting credentials such as client identifiers which belong to other DHCP clients.
• DHCP packets cannot travel across router.

-DR