H3C Technologies H3C SecPath F1000-E - Manual (Page 62)

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To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Enable the DHCP relay agent on
the current interface
dhcp select relay
Required
With DHCP enabled, interfaces
work in the DHCP server mode.
NOTE:
•
If the DHCP relay agent is enabled on an Ethernet subinterface, a packet received from a client on this
interface must contain a VLAN tag and the VLAN tag must be the same as the VLAN ID of the
subinterface; otherwise, the packet is discarded.
• If the DHCP client obtains an IP address via the DHCP relay agent, the address pool of the subnet to
which the IP address of the DHCP relay agent 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 requesting messages
from clients, the relay agent will forward them to all the DHCP servers of the group.
Follow these steps to correlate a DHCP server group with a relay agent interface:
To do… Use the command… Remarks
Enter system view system-view —
Create a DHCP server group and
add a server into the group dhcp relay server-group group-id ip
ip-address Required
Not created by default.
Enter interface view
interface interface-type
interface-number
—
Correlate the DHCP server group
with the current interface
dhcp relay server-select group-id
Required
By default, no interface is
correlated with any DHCP
server group.
NOTE:
•
You can specify up to twenty DHCP server groups on the relay agent and up to eight DHCP server
addresses for each DHCP server group.
• 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, while a relay
agent interface can only correlate with one DHCP server group. Using the dhcp relay server-select
command repeatedly overwrites the previous configuration. However, if the specified DHCP server
group does not exist, the interface still uses the previous correlation.