What is DHCP? – Dynamic Host Configuration Protocol Explained

What is DHCP?

DHCP (Dynamic Host Configuration Protocol) is a network protocol that automatically assigns IP addresses and other network configuration to devices. Without DHCP, every device would need to be manually configured with an IP address, subnet mask, default gateway and DNS server.

ProtocolUDP port 67 (server) / 68 (client)

RFCRFC 2131

SuccessorDHCPv6 for IPv6 networks

The DORA Process

When a device connects to a network, DHCP uses a 4-step process called DORA:

Discover

Client broadcasts: "Is there a DHCP server?"

Offer

Server responds: "Here is an available IP address"

Request

Client: "I would like that IP address please"

Acknowledge

Server: "Confirmed – the IP is yours for [lease time]"

What DHCP assigns

IP Addresse.g. 192.168.1.42

Subnet Maske.g. 255.255.255.0

Default Gatewaye.g. 192.168.1.1

DNS Servere.g. 1.1.1.1

Lease timee.g. 24 hours

DHCP vs Static IP

DHCPAutomatic, easy, for most devices

StaticManual, fixed, for servers/printers

DHCP ReservationFixed IP via MAC address – best of both

Knowledge IPv4 Detail Subnet IP Lookup My IP

DHCP – automatic IP address management

DHCP (Dynamic Host Configuration Protocol) eliminates the need to manually configure IP addresses on every device in a network. When a device connects, it goes through the DORA process (Discover, Offer, Request, Acknowledge) to receive an IP address, subnet mask, gateway and DNS server automatically. DHCP is used in home routers, corporate networks and ISP infrastructure. For devices that need a consistent IP (servers, printers, NAS), a DHCP reservation assigns a fixed IP based on the device's MAC address.