UMN:CLI
User Manual
V5824G
288
8.5.4.3
DHCP Server ID Option
In case that more than two DHCP servers are connected to one DHCP relay agent, if the
relay agent is supposed to broadcast the DHCP_DISCOVER message sent from a DHCP
client to all connected DHCP servers, and then the servers will return DHCP_OFFER
message. The relay agent, however, will forward only one DHCP_OFFER message of the
responses from the servers to the DHCP client. The DHCP client will try to respond to the
server which sent the DHCP_OFFER with DHCP_REQUEST message, but the relay
agent broadcasts it to all the DHCP servers again.
To prevent the unnecessary broadcast like this, you can configure a DHCP relay agent to
aware the server ID. This will allow the DHCP relay agent to forward DHCP_REQUEST
message to only one DHCP server with the unicast form under the multiple server
environment.
To enable/disable a DHCP relay agent to recognize the DHCP server ID option in the
forwarded DHCP_REQUEST message, use the following command.
Command
Mode
Description
ip dhcp relay aware-server-id
Global
Enables the system to recognize the DHCP server ID
in the DHCP_REQUEST message.
no ip dhcp relay aware-server-id
Disables the DHCP server ID recognition option.
8.5.4.4
DHCP Relay Statistics
To display DHCP relay statistics, use the following command.
Command
Mode
Description
show ip dhcp relay statistics all
Enable
Global
Bridge
Shows DHCP relay statistics for all the interfaces.
show ip dhcp relay statistics
vlan
VLANS
Shows DHCP relay statistics for a specified VLAN.
To delete collected DHCP relay statistics, use the following command.
Command
Mode
Description
clear ip dhcp relay statistics
Enable
Global
Bridge
Deletes collected DHCP relay statistics.