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Enabling client offline detection on the DHCP relay agent
The client offline detection on the DHCP relay agent detects the user online status based on the ARP
entry aging. When an ARP entry ages out, the DHCP client offline detection feature deletes the relay
entry for the IP address and sends a RELEASE message to the DHCP server.
The feature does not function if an ARP entry is manually deleted.
To enable client offline detection on the DHCP relay agent:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable the relay agent to
record relay entries.
dhcp relay
client-information record
By default, the relay agent does not
record relay entries.
Without relay entries, client offline
detection cannot function correctly.
3.
Enter interface view.
interface interface-type
interface-number
N/A
4.
Enable the DHCP relay agent.
dhcp select relay
By default, when DHCP is enabled,
an interface operates in the DHCP
server mode.
5.
Enable client offline detection.
dhcp client-detect
By default, client offline detection is
disabled on the DHCP relay agent.
Configuring the DHCP relay agent to release an
IP address
Configure the relay agent to release the IP address for a relay entry. The relay agent sends a
DHCP-RELEASE message to the server and meanwhile deletes the relay entry. Upon receiving the
DHCP-RELEASE message, the DHCP server releases the IP address.
To configure the DHCP relay agent to release an IP address:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the DHCP relay
agent to release an IP
address.
dhcp relay release ip
ip-address
[
vpn-instance
vpn-instance-name
]
This command can release only
the IP addresses in the recorded
relay entries.
Configuring Option 82
To support Option 82, you must perform related configuration on both the DHCP server and relay
agent. For DHCP server Option 82 configuration, see "
Enabling handling of Option 82
."
To configure Option 82:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
