H3C Technologies H3C S5560 Series Switches - Manual (Page 74)

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Step Command Remarks
2. Set the aging time for MAC
address check entries. dhcp relay check mac-address
aging-time time
The default aging time is 300
seconds.
This command takes effect only
after you execute the dhcp relay
check mac-address command.
3. Enter the interface view.
interface interface-type
interface-number
N/A
4. Enable MAC address check. dhcp relay check mac-address
By default, MAC address check
is disabled.
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 client-ip
[ vpn-instance vpn-instance-name ]
This command can release only the
IP addresses in the recorded relay
entries.
Configuring Option 82
Follow these guidelines when you configure 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 ."
• The device name (sysname) must not include spaces if it is configured as the padding content for
sub-option 1. Otherwise, the DHCP relay agent fails to add or replace Option 82..
To configure Option 82:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Enable the relay agent to handle
Option 82.
dhcp relay information enable
By default, handling of
Option 82 is disabled.