Archive for 9月 13, 2013

CentOS一键配置iptables防火墙

CentOS一键配置iptables防火墙
手里几台VPS配置iptables太繁琐,看到了朱哥的LNMP脚本里有一个自动配置iptables防火墙的脚本,借来改了一下,给需要的人用;
只提供常用端口的设置,如果你有特殊需求只需自行添加或减少相应的端口即可;

使用方法:

wget -c http://ph4ntasy.googlecode.com/files/iptables.sh
chmod +x iptables.sh
./iptables.sh
设置iptables开机自动启动:

chkconfig –level 345 iptables on
完整Shell:

#!/bin/bash
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH
function support_distro(){
if [ -z “`egrep -i “centos” /etc/issue`” ];then
echo “Sorry,iptables script only support centos system now.”
exit 1
fi
}
support_distro
echo “============================iptables configure============================================”
# Created by Centos.bz Modified by ph4ntasy.com
# Only support CentOS system
# 获取SSH端口
if grep “^Port” /etc/ssh/sshd_config>/dev/null;then
sshdport=`grep “^Port” /etc/ssh/sshd_config | sed “s/Ports//g” `
else
sshdport=22
fi
# 获取DNS服务器IP
if [ -s /etc/resolv.conf ];then
nameserver1=`cat /etc/resolv.conf |grep nameserver |awk ‘NR==1{print $2 }’`
nameserver2=`cat /etc/resolv.conf |grep nameserver |awk ‘NR==2{print $2 }’`
fi
IPT=”/sbin/iptables”
# 删除已有规则
$IPT –delete-chain
$IPT –flush
# 禁止进,允许出,允许回环网卡
$IPT -P INPUT DROP
$IPT -P FORWARD DROP
$IPT -P OUTPUT ACCEPT
$IPT -A INPUT -i lo -j ACCEPT
# 允许已建立的或相关连接的通行
$IPT -A INPUT -m state –state RELATED,ESTABLISHED -j ACCEPT
$IPT -A OUTPUT -m state –state RELATED,ESTABLISHED -j ACCEPT
# 限制80端口单个IP的最大连接数为10
$IPT -I INPUT -p tcp –dport 80 -m connlimit –connlimit-above 10 -j DROP
# 允许80(HTTP)/873(RSYNC)/443(HTTPS)/20,21(FTP)/25(SMTP)端口的连接
$IPT -A INPUT -p tcp -m tcp –dport 80 -j ACCEPT
$IPT -A INPUT -p tcp -m tcp –dport 873 -j ACCEPT
$IPT -A INPUT -p tcp -m tcp –dport 443 -j ACCEPT
$IPT -A INPUT -p tcp -m tcp –dport 20 -j ACCEPT
$IPT -A INPUT -p tcp -m tcp –dport 21 -j ACCEPT
$IPT -A INPUT -p tcp -m tcp –dport 25 -j ACCEPT
# 允许SSH端口的连接,脚本自动侦测目前的SSH端口,否则默认为22端口
$IPT -A INPUT -p tcp -m tcp –dport $sshdport -j ACCEPT
# 允许ping
$IPT -A INPUT -p icmp -m icmp –icmp-type 8 -j ACCEPT
$IPT -A INPUT -p icmp -m icmp –icmp-type 11 -j ACCEPT
# 允许DNS
[ ! -z “$nameserver1” ] && $IPT -A OUTPUT -p udp -m udp -d $nameserver1 –dport 53 -j ACCEPT
[ ! -z “$nameserver2” ] && $IPT -A OUTPUT -p udp -m udp -d $nameserver2 –dport 53 -j ACCEPT
# 保存规则并重启IPTABLES
service iptables save
service iptables restart
echo “============================iptables configure completed============================================”

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利用iptables防止php-ddos对外udp发包

利用iptables防止php-ddos对外udp发包
最近php-ddos泛滥,尤其是织梦一堆洞洞,你懂得,我们可以利用iptables,从根源上禁止php-ddos对外发包。

首选允许需要UDP服务的端口(如DNS)

iptables -I OUTPUT -p udp –dport 53 -d 8.8.8.8 -j ACCEPT
iptables -I OUTPUT -p udp –dport 53 -d 8.8.4.4 -j ACCEPT
“53”,为DNS所需要的UDP端口,“8.8.8.8”部分为DNS IP,根据您服务器的设定来定,若您不知您当前服务器使用的DNS IP,可在SSH中执行以下命令获取:

cat /etc/resolv.conf |grep nameserver |awk ‘NR==1{print $2 }’
禁止本机对外发送UDP包

iptables -A OUTPUT -p udp -j DROP

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