Ubuntu安装CSF防火墙

1. 安装
Login as the root user to SSH and run the following commands.
rm -fv csf.tgz
wget http://www.configserver.com/free/csf.tgz

apt-get install libwww-perl
tar -xzf csf.tgz
cd csf
sh install.sh

2. 防范DDOS攻击
Step 1 :  Open the CSF configuration file /etc/csf/csf.conf
Step 2 : In that search for option called CT_LIMIT, by default it will be like CT_LIMIT=0 , change this to CT_LIMIT=90 ,here 90 is the max no.of connections from an IP to your server ( choose this value according to your server usage )

Step 3:Now search for option called CT_PORTS.This option is used to specify the port for which you want prevent DOS attack.Since our aim is to prevent the DOS attck to apache – port 80 , change CT_PORTS = “” to CT_PORTS = “80″

3. 限制每个IP连接数

COnNLIMIT= "80;7"

4. PT_LIMIT = "0" 禁止程序内存不足时，发邮件