Configuring DHCP snooping entry auto backup

The auto backup feature saves DHCP snooping entries to a backup file, and allows the DHCP snooping device to download the entries from the backup file at device reboot. The entries on the DHCP snooping device cannot survive a reboot. The auto backup helps the security features provide services if these features (such as IP source guard) must use DHCP snooping entries for user authentication.

If you disable DHCP snooping with the undo dhcp snooping enable command, the device deletes all DHCP snooping entries, including those stored in the backup file.

1. Enter system view.

   system-view

2. Configure the DHCP snooping device to back up DHCP snooping entries to a file.

   dhcp snooping binding database filename { filename | url url [ username username [ password { cipher | simple } string ] ] }

   By default, the DHCP snooping device does not back up DHCP snooping entries.

   With this command executed, the DHCP snooping device backs up DHCP snooping entries immediately and runs auto backup.

   This command automatically creates the file if you specify a non-existent file.

3. (Optional.) Manually save DHCP snooping entries to the backup file.

   dhcp snooping binding database update now

4. (Optional.) Set the waiting time after a DHCP snooping entry change for the DHCP snooping device to update the backup file.

   dhcp snooping binding database update interval interval

   By default, the DHCP snooping device waits 300 seconds to update the backup file after a DHCP snooping entry change. If no DHCP snooping entry changes, the backup file is not updated.