Before the switch enabled with automatic backup of the dynamic DHCP snooping binding table restarts, it saves the dynamic DHCP binding table to the flash memory or CF card. After the switch restarts, it reads the file to restore the dynamic DHCP binding table. The possible causes for restoration failure are as follows:

1. It takes a long period of time to restart the switch after power-off. As a result, the lease for saving the dynamic DHCP binding table expires.

2. Writing the file takes a long period of time, so the file cannot be updated immediately when binding entries are added or deleted. Binding entries in the file may be not synchronized with binding entries on the switch.

Solution: Run the dhcp snooping user-bind auto-save command again before the switch restarts, and then save the configuration and restart the switch.