So, 3500 is a BIG increase over 100...will this cause any issues?
# 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