brute_force(){
   echo -n "Preventing Brute Force Attacks..."

   ## Create New Chain
   iptables -N BRUTE_FORCE

   ## FTP/Telnet/SSH
   iptables -A INPUT -i $LAN_IF -p tcp -m conntrack --ctstate NEW -m multiport --dports 21,22,23 -j BRUTE_FORCE
   iptables -A BRUTE_FORCE -m recent --hitcount 2 --rcheck --seconds 15 --name brute_force -m limit --limit 10/min -j ULOG --ulog-prefix "[BRUTE_FORCE DROP]: "
   iptables -A BRUTE_FORCE -m recent --hitcount 2 --update --seconds 15 --name brute_force -j DROP
   iptables -A BRUTE_FORCE -m recent --set --name brute_force -j RETURN
}