The user's backup machine found today that the management interface cannot be accessed. The customer described that he could ping successfully before, but suddenly couldn't ping successfully today.

Checked the backup node ARP table and there is no arp entry of the OOB backup router, disable and enable the fxp0 interface doesn't help. Manually add the ARP entry of the OOB gateway and issue still can't fixed.

This should be the fxp0 stuck, reboot this backup node and the issue has been fixed.