DHCP

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network parameters to devices when they join a network. It eliminates manual address configuration, manages address pools, and provides lease-based allocation so addresses return to the pool when no longer needed.

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DHCP

DHCP gives a device the network settings it needs to communicate. The name stands for Dynamic Host Configuration Protocol.

Without DHCP, you would enter an address and related settings on every device. That approach can work for a few stable systems. It becomes slow and error-prone when laptops, phones, virtual machines, and other clients appear and disappear.

DHCP centralizes that work. A client asks for configuration. A server selects settings for that client. The result is a binding between the client and a collection of parameters.

The core problem

An IP address alone is rarely enough. An IPv4 client commonly also needs a subnet mask, a default router, and one or more DNS server addresses. DHCP carries these values as options.

The server can allocate an address for a limited period called a lease. A lease lets the server reuse an address after the client stops using it. The client can request an extension before the lease expires.

DHCP also supports fixed allocation. An administrator can arrange for a known client to receive stable parameters. DHCP is therefore more than random address assignment. It is a protocol for controlled delivery of host configuration.

The four roles

The client requests configuration. It usually begins before it has a usable address.

DHCP

The core problem

The four roles

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