edit /etc/sysconfig/iptables and add -A FORWARD -j ACCEPT -p all -s 0/0 -i venet0 -A FORWARD -j ACCEPT -p all -s 0/0 -o venet0 -A INPUT -i venet0 -j ACCEPT -A OUTPUT -o venet0 -j ACCEPT create file /etc/csf/csfpre.sh and enter all the extra rules directly into it prefixed with "iptables" so the contents of that file should look something like: iptables -A INPUT -i venet0 -j ACCEPT iptables -A OUTPUT -o venet0 -j ACCEPT iptables -A FORWARD -j ACCEPT -p all -s 0/0 -i venet0 iptables -A FORWARD -j ACCEPT -p all -s 0/0 -o venet0 edit /etc/csf/csf.conf file and add and search for ETH_DEVICE = "" change to ETH_DEVICE = "venet+" (as their is no eth0 in a VPS).
You'll also want to make sure your host has the iptables modules loaded for a firewall to work properly.