In some configurations Your Local Router may have to ask the ISP’s Router for a DHCP Address, in this scenario your Router is a DHCP Client
To configure an Ethernet interface as a DHCP client, use the
Local-Router(config-if)# ip address dhcp
interface configuration mode command
The interface connected to the ISP is configured as the DHCP Client, for example G0/0/1 interface is configured with the ip address dhcp command in the figure