Limit the number of IP's kept in the /etc/csf/csf.deny file. This can be
important as a large number of IP addresses create a large number of iptables
rules (4 times the number of IP's) which can cause problems on some systems
where either the the number of iptables entries has been limited (esp VPS's)
or where resources are limited. This can result in slow network performance,
or, in the case of iptables entry limits, can prevent your server from
booting as not all the required iptables chain settings will be correctly
configured.