64Configuring the DHCP clientWith DHCP client enabled, an interface uses DHCP to obtain configuration parameters from the DHCPserver, for example, an IP address.The DHCP client configuration is supported only on Layer 3 Ethernet interfaces (or subinterfaces) andVLAN interfaces.When multiple VLAN interfaces with the same MAC address use DHCP for IP address acquisitionthrough a relay agent, the DHCP server cannot be a Windows Server 2000 or Windows Server 2003.Enabling the DHCP client on an interfaceFollow these guidelines when you enable the DHCP client on an interface:• On some device models, if the number of IP address request failures reaches the system-definedamount, the DHCP client-enabled interface uses a default IP address.• An interface can be configured to acquire an IP address in multiple ways. The new configurationoverwrites the old.• Secondary IP addresses cannot be configured on an interface that is enabled with the DHCP client.• If the interface obtains an IP address on the same segment as another interface on the device, theinterface does not use the assigned address. Instead, it requests a new IP address from the DHCPserver.To enable the DHCP client on an interface:Step Command Remarks1. Enter system view. system-view N/A2. Enter interface view. interface interface-typeinterface-number N/A3. Configure an interface to useDHCP for IP addressacquisition.ip address dhcp-allocBy default, an interface does notuse DHCP for IP addressacquisition.Configuring a DHCP client ID for an interfaceA DHCP client ID is added to the DHCP option 61. A DHCP server can specify IP addresses for clientsbased on the DHCP client ID.Make sure the IDs for different DHCP clients are unique.To configure a DHCP client ID for an interface:Step Command Remarks1. Enter system view. system-view N/A
