H3C Technologies H3C S12500 Series Switches - Manual (Page 73)

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Step Command Remarks
3. Enable the DHCP relay
agent on the current
interface.
dhcp select relay
With DHCP enabled, interfaces operate in
the DHCP server mode.
NOTE:
If the DHCP client obtains an IP address through the DHCP relay agent, the address pool of the subnet to
which the IP address of the DHCP relay agent's interface connecting the DHCP client belongs must be
configured on the DHCP server. Otherwise, the DHCP client cannot obtain a correct IP address.
Correlating a DHCP server group with a relay
agent interface
To improve reliability, you can specify several DHCP servers as a group on the DHCP relay agent and
correlate a relay agent interface with the server group. When the interface receives request messages
from clients, the relay agent will forward them to all the DHCP servers of the group.
Configuration guidelines
Follow these guidelines when you correlate a DHCP server group with a relay agent interface:
• You can specify up to 20 DHCP server groups on the relay agent and eight DHCP server addresses
for each DHCP server group.
• You can specify up to eight DHCP server addresses for each DHCP server group.
• The IP addresses of DHCP servers and those of relay agent's interfaces that connect DHCP clients
cannot be on the same subnet. Otherwise, the client cannot obtain an IP address.
• The IP addresses of DHCP servers and those of relay agent's interfaces cannot be on the same
subnet. Otherwise, the client cannot obtain an IP address.
• A DHCP server group can correlate with one or multiple DHCP relay agent interfaces, but a relay
agent interface can only correlate with one DHCP server group. If you use the dhcp relay
server-select command multiple times, the most recent configuration takes effect. However, if the
specified DHCP server group does not exist, the interface still uses the previous correlation.
• The group-id in the dhcp relay server-select command was specified by the dhcp relay
server-group command.
Configuration procedure
To correlate a DHCP server group with a relay agent interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Create a DHCP server group
and add a server into the
group.
dhcp relay server-group group-id
ip ip-address
Not created by default.