H3C Technologies H3C S12500 Series Switches - Manual (Page 70)

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Configuring the DHCP relay agent
The DHCP relay agent configuration is supported only on Layer 3 Ethernet interfaces (or subinterfaces),
VLAN interfaces, and Layer 3 aggregate interfaces.
Introduction to DHCP relay agent
Application environment
Through a relay agent, DHCP clients can communicate with a DHCP server on another subnet to obtain
configuration parameters. Thus, DHCP clients on different subnets can contact the same DHCP server
rather than having a DHCP server on each subnet.
An MCE switch serving as the DHCP relay agent can forward DHCP packets not only between a DHCP
server and clients on a public network, but also between a DHCP server and clients on a private network.
Note that the IP address ranges of the public and private networks or those of private networks cannot
overlap each other. For more information about MCE, see MPLS Configuration Guide.
Fundamentals
Figure 30 DHCP relay agent application
The DHCP server and client interact with each other in a similar way with or without a relay agent (see
"
DHCP overview ".)