Has the firewall csf along with lfd crashed in your server ? When trying to restart the service, you might find the following error :

Starting lfd:

Error: You have an unresolved error when starting csf. You need to restart csf successfully before starting lfd (see /etc/csf/csf.error)
[ OK ]

– Check the file /etc/csf/csf.error to see if you can spot the error. If the file is empty, the service might have gotten too old.

Upgrade csf/lfd to the new version by running the following script :

# csf -u