Configuring The Dhcp Relay Agent To Always Unicast Relayed Dhcp Responses; Configuring Forwarding Dhcp Replies Based On Option 82 - H3C SR8800-F Configuration Manual

Step
3. Specify the source IP address
for DHCP requests.
Configuring the DHCP relay agent to always
unicast relayed DHCP responses
This feature enables the DHCP relay agent to ignore the broadcast flag and always unicast relayed
responses. This feature is useful in some LANs, such as a WLAN network, where broadcast
communication is not recommended.
To configure the DHCP relay agent to always unicast relayed DHCP responses:
Step
1. Enter system view.
2. Enable the DHCP relay agent
to always unicast relayed
DHCP responses.
Configuring forwarding DHCP replies based on
Option 82
Configure this feature if the DHCP relay agent is required to forward DHCP replies to DHCP clients
based on Option 82.
For example, an IPRAN network has a primary gateway and a secondary gateway. An L3VE
interface is configured as the relay interface on each of the gateways. Multiple L2VE subinterfaces
are configured to receive packets. One L2VE subinterface corresponds to one PW. Only the primary
gateway receives DHCP requests, but both the primary and secondary gateways might receive
DHCP replies. The primary gateway can forward DHCP replies based on locally recorded user
information, but the secondary gateway cannot. The secondary gateway can only forward DHCP
replies to all PWs.
To enable the secondary gateway to forward a DHCP reply to only the intended PW, perform the
following tasks:
•
Configure the dhcp relay information enable and dhcp relay information circuit-id (with
sub-interface-vlan specified) commands on the primary gateway. Then, when the primary
gateway receives a DHCP request, it adds Option 82 to the reply and record the VLAN ID of the
L2VE subinterface.
•
Configure the dhcp relay information enable, dhcp relay information circuit-id (with
sub-interface-vlan specified), and dhcp relay forward reply by-option82 commands on the
Command
dhcp relay source-address
{ ip-address [ option { 60
[ option-text ] | code } ] |
gateway | relay-interface }
Command
system-view
dhcp relay always-unicast
146
Remarks
By default, the DHCP relay agent
uses the primary IP address of the
interface that connects to the DHCP
server as the source IP address for
DHCP requests. If this interface
does not have an IP address, the
DHCP relay agent uses an IP
address that shares the same
subnet with the DHCP server.
You can specify only one source IP
address for DHCP requests on an
interface.
Remarks
N/A
By default, the DHCP relay agent
reads the broadcast flag to decide
whether to broadcast or unicast a
response.