Dynamic Host Configuration Protocol
DHCP is a mechanism for automatically allocating IP addresses to devices placed on a network.
In order for a network device to exchange data with another device on the network, an IP address needs to be assigned to the device.
The IP address represents the address of the device. Therefore, nothing can be sent to the device without knowing its address.
Without using DHCP, IP addresses can be assigned to devices manually. However, it is difficult to manage them and network failures due to duplicate IP addresses can be caused.
DHCP is a mechanism that can solve these problems.
The reason why you can use the Internet immediately when connecting to it with a router and a LAN cable without configuring any special settings is that DHCP assigns IP addresses to devices on the network.
The side to which an IP address is assigned by DHCP is referred to as a "DHCP client".
The side that assigns IP addresses by DHCP is referred to as a "DHCP server".