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Configuring the DHCP relay agent
About DHCP relay agent
The DHCP relay agent enables clients to get IP addresses and configuration parameters from a
DHCP server on another subnet.
shows a typical application of the DHCP relay agent.
Figure 39 DHCP relay agent application
DHCP relay agent operation
The DHCP server and client interact with each other in the same way regardless of whether the relay
agent exists. For the interaction details, see "
." The following only
describes steps related to the DHCP relay agent:
1.
After receiving a DHCP-DISCOVER or DHCP-REQUEST broadcast message from a DHCP
client, the DHCP relay agent processes the message as follows:
a.
Fills the
giaddr
field of the message with its IP address.
b.
Unicasts the message to the designated DHCP server.
2.
Based on the
giaddr
field, the DHCP server returns an IP address and other configuration
parameters in a response.
3.
The relay agent conveys the response to the client.
