Blocking synflood with CSF

Kidades

Registered
Feb 24, 2017
3
0
1
Serbia
cPanel Access Level
Root Administrator
My server is currently under a synflood attack. I've enabled synflood protection in CSF with the following settings

SYNFLOOD
= On
SYNFLOOD_RATE
= 20/s
SYNFLOOD_BURST
= 10

It seems to be successfully detecting them, as my log/messages is filled with
... server kernel: [ 944.509361] Firewall: *SYNFLOOD Blocked* IN=eth0 ...

However, those IPs are not getting blocked (added to the deny list). I have to manually add them in order to stop the attack.

How can I make CSF automatically add the IP to the block list once a synflood attack from it is detected?