Enabling periodic refresh of dynamic relay entries
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 the following information to periodically send a DHCP-REQUEST message to the DHCP server:
The IP address of a relay entry.
The MAC address of the DHCP relay interface.
The relay agent maintains the relay entries depending on what it receives from the DHCP server:
If the server returns a DHCP-ACK message or does not return any message within an interval, the DHCP relay agent removes the relay entry. In addition, upon receiving the DHCP-ACK message, the relay agent sends a DHCP-RELEASE message to release the IP address.
If the server returns a DHCP-NAK message, the relay agent keeps the relay entry.
To enable periodic refresh of dynamic relay entries:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enable periodic refresh of dynamic relay entries. | dhcp relay client-information refresh enable | By default, periodic refresh of dynamic relay entries is enabled. |
3. Set the refresh interval. | dhcp relay client-information refresh [ auto | interval interval ] | By default, the refresh interval is auto, which is calculated based on the number of total relay entries. |