公司的产品一直运行在云服务器上，从而有幸接触过aws的ec2，盛大的云服务器，最近准备有使用阿里云的弹性计算（云服务器）。前两种云服务器在安全策略这块做的比较好，提供简单明了的配置界面，而且给了默认的安全策略，反观阿里云服务器，安全策略需要自己去配置，甚至centos机器上都没有预装iptables（起码我们申请两台上都没有），算好可以使用yum来安装，安装命令如下：
yum install -y iptables
iptables安装好后就可以来配置规则了。由于作为web服务器来使用，所以对外要开放 80 端口，另外肯定要通过ssh进行服务器管理，22 端口也要对外开放，当然最好是把ssh服务的默认端口改掉，在公网上会有很多人试图破解密码的，如果修改端口，记得要把该端口对外开发，否则连不上就悲剧了。下面提供配置规则的详细说明：
第一步：清空所有规则 当Chain INPUT (policy DROP)时执行/sbin/iptables -F后，你将和服务器断开连接 所有在清空所有规则前把policy DROP该为INPUT，防止悲剧发生，小心小心再小心 /sbin/iptables -P INPUT ACCEPT 清空所有规则 /sbin/iptables -F /sbin/iptables -X 计数器置0 /sbin/iptables -Z 第二步：设置规则 允许来自于lo接口的数据包，如果没有此规则，你将不能通过127.0.0.1访问本地服务，例如ping 127.0.0.1 /sbin/iptables -A INPUT -i lo -j ACCEPT 开放TCP协议22端口，以便能ssh，如果你是在有固定ip的场所，可以使用 -s 来限定客户端的ip /sbin/iptables -A INPUT -p tcp --dport 22 -j ACCEPT 开放TCP协议80端口供web服务 /sbin/iptables -A INPUT -p tcp --dport 80 -j ACCEPT 10.241.121.15是另外一台服务器的内网ip，由于之间有通信，接受所有来自10.241.121.15的TCP请求 /sbin/iptables -A INPUT -p tcp -s 10.241.121.15 -j ACCEPT 接受ping /sbin/iptables -A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT 这条规则参看：http://www.netingcn.com/iptables-localhost-not-access-internet.html /sbin/iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT 屏蔽上述规则以为的所有请求，不可缺少，否则防火墙没有任何过滤的功能 /sbin/iptables -P INPUT DROP 可以使用 iptables -L -n 查看规则是否生效
至此防火墙就算配置好，但是这是临时的，当重启iptables或重启机器，上述配置就会被清空，要想永久生效，还需要如下操作：
/etc/init.d/iptables save 或 service iptables save 执行上述命令可以在文件 /etc/sysconfig/iptables 中看到配置
以下提供一个干净的配置脚本：
/sbin/iptables -P INPUT ACCEPT /sbin/iptables -F /sbin/iptables -X /sbin/iptables -Z /sbin/iptables -A INPUT -i lo -j ACCEPT /sbin/iptables -A INPUT -p tcp --dport 22 -j ACCEPT /sbin/iptables -A INPUT -p tcp --dport 80 -j ACCEPT /sbin/iptables -A INPUT -p tcp -s 10.241.121.15 -j ACCEPT /sbin/iptables -A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT /sbin/iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT /sbin/iptables -P INPUT DROP
最后执行 service iptables save ，先确保ssh连接没有问题，防止规则错误，导致无法连上服务器，因为没有save，重启服务器规则都失效，否则就只有去机房才能修改规则了。也可以参考：ubuntu iptables 配置脚本来写一个脚本。
最后再次提醒，在清空规则之前一定要小心，确保Chain INPUT (policy ACCEPT)。
补充阿里云的linux_drop_port.sh
#!/bin/bash
#########################################
#Function: linux drop port
#Usage: bash linux_drop_port.sh
#Author: Customer Service Department
#Company: Alibaba Cloud Computing
#Version: 2.0
#########################################
check_os_release()
{
while true
do
os_release=$(grep "Red Hat Enterprise Linux Server release"/etc/issue 2>/dev/null)
os_release_2=$(grep "Red Hat Enterprise Linux Server release"/etc/redhat-release 2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep "release 5" >/dev/null2>&1
then
os_release=redhat5
echo "$os_release"
elif echo "$os_release"|grep "release 6">/dev/null 2>&1
then
os_release=redhat6
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
os_release=$(grep "Aliyun Linux release" /etc/issue2>/dev/null)
os_release_2=$(grep "Aliyun Linux release" /etc/aliyun-release2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep "release 5" >/dev/null2>&1
then
os_release=aliyun5
echo "$os_release"
elif echo "$os_release"|grep "release 6">/dev/null 2>&1
then
os_release=aliyun6
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
os_release=$(grep "CentOS release" /etc/issue 2>/dev/null)
os_release_2=$(grep "CentOS release" /etc/*release2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep "release 5" >/dev/null2>&1
then
os_release=centos5
echo "$os_release"
elif echo "$os_release"|grep "release 6">/dev/null 2>&1
then
os_release=centos6
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
os_release=$(grep -i "ubuntu" /etc/issue 2>/dev/null)
os_release_2=$(grep -i "ubuntu" /etc/lsb-release2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep "Ubuntu 10" >/dev/null2>&1
then
os_release=ubuntu10
echo "$os_release"
elif echo "$os_release"|grep "Ubuntu 12.04">/dev/null 2>&1
then
os_release=ubuntu1204
echo "$os_release"
elif echo "$os_release"|grep "Ubuntu 12.10">/dev/null 2>&1
then
os_release=ubuntu1210
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
os_release=$(grep -i "debian" /etc/issue 2>/dev/null)
os_release_2=$(grep -i "debian" /proc/version 2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep "Linux 6" >/dev/null2>&1
then
os_release=debian6
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
os_release=$(grep "openSUSE" /etc/issue 2>/dev/null)
os_release_2=$(grep "openSUSE" /etc/*release 2>/dev/null)
if [ "$os_release" ] && [ "$os_release_2" ]
then
if echo "$os_release"|grep"13.1" >/dev/null 2>&1
then
os_release=opensuse131
echo "$os_release"
else
os_release=""
echo "$os_release"
fi
break
fi
break
done
}
exit_script()
{
echo -e "\033[1;40;31mInstall $1 error,will exit.\n\033[0m"
rm-f $LOCKfile
exit 1
}
config_iptables()
{
iptables -I OUTPUT 1 -p tcp -m multiport --dport21,22,23,25,53,80,135,139,443,445 -j DROP
iptables -I OUTPUT 2 -p tcp -m multiport --dport 1433,1314,1521,2222,3306,3433,3389,4899,8080,18186-j DROP
iptables -I OUTPUT 3 -p udp -j DROP
iptables -nvL
}
ubuntu_config_ufw()
{
ufwdeny out proto tcp to any port 21,22,23,25,53,80,135,139,443,445
ufwdeny out proto tcp to any port 1433,1314,1521,2222,3306,3433,3389,4899,8080,18186
ufwdeny out proto udp to any
ufwstatus
}
####################Start###################
#check lock file ,one time only let thescript run one time
LOCKfile=/tmp/.$(basename $0)
if [ -f "$LOCKfile" ]
then
echo -e "\033[1;40;31mThe script is already exist,please next timeto run this script.\n\033[0m"
exit
else
echo -e "\033[40;32mStep 1.No lock file,begin to create lock fileand continue.\n\033[40;37m"
touch $LOCKfile
fi
#check user
if [ $(id -u) != "0" ]
then
echo -e "\033[1;40;31mError: You must be root to run this script,please use root to execute this script.\n\033[0m"
rm-f $LOCKfile
exit 1
fi
echo -e "\033[40;32mStep 2.Begen tocheck the OS issue.\n\033[40;37m"
os_release=$(check_os_release)
if [ "X$os_release" =="X" ]
then
echo -e "\033[1;40;31mThe OS does not identify,So this script isnot executede.\n\033[0m"
rm-f $LOCKfile
exit 0
else
echo -e "\033[40;32mThis OS is $os_release.\n\033[40;37m"
fi
echo -e "\033[40;32mStep 3.Begen toconfig firewall.\n\033[40;37m"
case "$os_release" in
redhat5|centos5|redhat6|centos6|aliyun5|aliyun6)
service iptables start
config_iptables
;;
debian6)
config_iptables
;;
ubuntu10|ubuntu1204|ubuntu1210)
ufwenable <<EOF
y
EOF
ubuntu_config_ufw
;;
opensuse131)
config_iptables
;;
esac
echo -e "\033[40;32mConfig firewallsuccess,this script now exit!\n\033[40;37m"
rm -f $LOCKfile
上述文件下载到机器内部直接执行即可。