前言：网站被DDOS攻击了怎么办,一般只能 购买硬防来防护,若攻击不是很大,可参考如下使用脚本来屏蔽ip,注意：ddos是流量攻击,若攻击非常大则无法预防

1、安装DDOS deflate

wget http://www.moerats.com/usr/down/DDOS/deflate.sh
chmod +x deflate.sh
./deflate.sh

2、配置DDOS deflate
配置/usr/local/ddos/ddos.conf文件。

##### Paths of the script and other files
PROGDIR="/usr/local/ddos"
PROG="/usr/local/ddos/ddos.sh"
IGNORE_IP_LIST="/usr/local/ddos/ignore.ip.list"
CRON="/etc/cron.d/ddos.cron"
APF="/etc/apf/apf"
IPT="/sbin/iptables"

##### frequency in minutes for running the script
##### Caution: Every time this setting is changed, run the script with --cron
#####          option so that the new frequency takes effect
FREQ=1
##### How many connections define a bad IP Indicate that below.
NO_OF_CONNECTIONS=150
##### APF_BAN=1 (Make sure your APF version is atleast 0.96)
##### APF_BAN=0 (Uses iptables for banning ips instead of APF)
APF_BAN=0
##### KILL=0 (Bad IPs are'nt banned, good for interactive execution of script)
##### KILL=1 (Recommended setting)
KILL=1
##### An email is sent to the following address when an IP is banned.
##### Blank would suppress sending of mails
EMAIL_TO="root"
##### Number of seconds the banned ip should remain in blacklist.
BAN_PERIOD=600

标示说明：
NO_OF_CONNECTIONS=150最大连接数，超过会被屏蔽，默认即可
APF_BAN 默认是1，建议使用0，标示iptables限制
EMAIL_TO="" 填写邮箱账号，到时候有信息会发送到我们邮箱中
BAN_PERIOD=600 代表限制该IP 600秒