H3C SR8800-F Configuration Manual page 160

The relay agent initially encapsulates its primary IP address to the giaddr field before forwarding a
request to the DHCP server. If no DHCP-OFFER is received, the relay agent allows the client to send
a maximum of two requests to the DHCP server by using the primary IP address. If no
DHCP-OFFER is returned after two retries, the relay agent switches to a secondary IP address. If the
DHCP server still does not respond, the next secondary IP address is used. After the secondary IP
addresses are all tried and the DHCP server does not respond, the relay agent repeats the process
by starting from the primary IP address.
Without this feature, the relay agent only encapsulates the primary IP address to the giaddr field of
all requests.
On a relay agent where DHCP address pools and gateway addresses are configured, the smart
relay feature starts the process from the first gateway address. For more information, see
"Configuring smart relay to specify the DHCP relay agent address for the giaddr field in a network
with DHCP address
Configuring smart relay to specify the DHCP relay agent address for the giaddr field in a
common network
Step
1. Enter system view.
2. Enter interface view.
3. Enable the DHCP relay agent.
4. Assign primary and
secondary IP addresses to the
DHCP relay agent.
5. Return to system view.
6. Enable the DHCP smart relay
feature.
Configuring smart relay to specify the DHCP relay agent address for the giaddr field in a
network with DHCP address pools
Step
1. Enter system view.
2. Enter interface view.
3. Enable the DHCP relay agent.
4. Return to system view.
5. Create a DHCP address pool
and enter its view.
6. Specify gateway addresses
for the clients matching the
DHCP address pool.
pools."
Command
system-view
interface interface-type
interface-number
dhcp select relay
ip address ip-address
{ mask-length | mask } [ sub ]
quit
dhcp smart-relay enable
Command
system-view
interface interface-type
interface-number
dhcp select relay
quit
dhcp server ip-pool
pool-name
gateway-list
ip-address&<1-64>
[ export-route ]
144
Remarks
N/A
N/A
By default, an interface operates in
the DHCP server mode when DHCP
is enabled.
By default, the DHCP relay agent
does not have any IP addresses.
N/A
By default, the DHCP smart relay
feature is disabled.
Remarks
N/A
N/A
By default, an interface operates in
the DHCP server mode when DHCP
is enabled.
N/A
By default, no DHCP address pool
exists.
By default, the DHCP address pool
does not have any gateway
addresses.