DHCP relay keeps sending unknown Request messages

DHCP Server —— AS —— DHCP Relay agent —— Client

The switch S5130 is used as a DHCP relay agent. The device (mac: c025-xxxx-e7xx) connected to the switch correctly obtains the ip address 10.xx.xxx.2.

But after 1-2 minutes, the switch sends another request to get the same address 10.xx.xxx.2, but the "Client MAC Address (00:00:00:00:02:7b)" is different, and this happens every time the switch gets the address.

1. This mac address 00:00:00:00:02:7b does not exist in the current network. Try display mac-add, and the address does not exist. 

2. Check that the current network is configured with dhcp relay client-information record. After turning on this command, dhcp relay client-information refresh enable will be turned on by default. After this function is turned on, the DHCP relay uses the IP address obtained by the client to send a DHCP-REQUEST message to the DHCP server at a specified time.

This phenomenon is normal. If do not want to continue sending DHCP-REQUEST messages, undo the dhcp relay client-information record function.