H3C S6812 Series Command Reference Manual page 735

Syntax
dhcp relay client-information refresh enable
undo dhcp relay client-information refresh enable
Default
The DHCP relay agent periodically refreshes relay entries.
Views
System view
Predefined user roles
network-admin
Usage guidelines
A DHCP client unicasts a DHCP-RELEASE message to the DHCP server to release its IP address.
The DHCP relay agent conveys the message to the DHCP server and does not remove the
IP-to-MAC entry of the client.
With this feature, the DHCP relay agent uses a client's IP address to periodically send a
DHCP-REQUEST message to the DHCP server.
•
If the server returns a DHCP-ACK message or does not return any message within an interval,
the DHCP relay agent performs the following operations:
Removes the relay entry.

Sends a DHCP-RELEASE message to the DHCP server to release the IP address.

•
If the server returns a DHCP-NAK message, the relay agent keeps the entry.
With this feature disabled, the DHCP relay agent does not remove relay entries automatically. After a
DHCP client releases its IP address, you must use the reset dhcp relay client-information on the
relay agent to remove the corresponding relay entry.
Examples
# Disable periodic refresh of relay entries.
<Sysname> system-view
[Sysname] undo dhcp relay client-information refresh enable
Related commands
dhcp relay client-information record
dhcp relay client-information refresh
reset dhcp relay client-information
dhcp relay dhcp-server timeout
Use dhcp relay dhcp-server timeout to set the DHCP server response timeout time for DHCP
server switchover.
Use undo dhcp relay dhcp-server timeout to restore the default.
Syntax
dhcp relay dhcp-server timeout time
undo dhcp relay dhcp-server timeout
Default
The DHCP server response timeout time is 30 seconds.
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