4.0 CCNA - IP Services

4.6 DHCP Client and Relay Agents – Roles

DHCP Client Role and Configuration

A DHCP client is a device that uses the Dynamic Host Configuration Protocol (DHCP) to automatically obtain its IP configuration, such as IP address, subnet mask, default gateway, and DNS server information. The DHCP client sends a broadcast request to the DHCP server asking for IP configuration information, and the DHCP server responds with the requested information.

DHCP clients are typically found in end-user devices such as laptops, desktop computers, and mobile devices. Using DHCP eliminates the need for manual IP configuration and ensures that IP addresses are dynamically assigned and managed in a consistent and efficient manner.

The DHCP client software is built into the operating system of the device and is typically enabled by default. The DHCP client can be configured to receive its IP configuration information from a DHCP server located on the same network segment or from a DHCP relay agent located on a different network segment.

DHCP client configuration on a Cisco IOS device

Cisco IOS devices typically act as DHCP servers, not clients. However, if a Cisco IOS device needs to obtain its IP configuration information from a DHCP server, it can be configured as a DHCP client.

To configure a Cisco IOS device as a DHCP client, the following steps can be taken:

1. Enable the interface on which the DHCP client will operate:

interface <interface-name>
no shutdown

2. Assign the interface an IP address of 0.0.0.0:

interface <interface-name>
ip address 0.0.0.0 0.0.0.0

3. Configure the interface as a DHCP client:

goCopy code
interface <interface-name>
ip address dhcp

4. Verify the DHCP client configuration:

show ip interface <interface-name>

Note: The specific configuration steps may vary based on the version of the Cisco IOS software