阿里云linux服务器安全设置(防火墙策略等)

首先需要进行linux的基础安全设置，可以先参考这篇文章

1、linux系统脚本

#!/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。

2、设置iptables，限制访问

/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 --dport 8080 -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
 service iptables save

以上脚本，在每次重装完系统后执行一次即可，其配置会保存至/etc/sysconfig/iptables

更详细的可以参考这篇文章

3、常用网络监控命令
（1） netstat -tunl：查看所有正在监听的端口

[root@ay1407041017110375bbz ~]# netstat -tunl
active internet connections (only servers)
proto recv-q send-q local address    foreign address    state  
tcp  0  0 0.0.0.0:22     0.0.0.0:*     listen  
udp  0  0 ip:123   0.0.0.0:*        
udp  0  0 ip:123   0.0.0.0:*        
udp  0  0 127.0.0.1:123    0.0.0.0:*        
udp  0  0 0.0.0.0:123     0.0.0.0:* 

其中123端口用于ntp服务。
（2）netstat -tunp：查看所有已连接的网络连接状态，并显示其pid及程序名称。

[root@ay1407041017110375bbz ~]# netstat -tunp
active internet connections (w/o servers)
proto recv-q send-q local address               foreign address             state       pid/program name   
tcp        0     96 ip:22            221.176.33.126:52699        established 926/sshd            
tcp        0      0 ip:34385         42.156.166.25:80            established 1003/aegis_cli 

根据上述结果，可以根据需要kill掉相应进程。
如:
kill -9 1003

（3）netstat -tunlp
（4）netstat常用选项说明：

-t: tcp  
-u : udp
-l, --listening
       show only listening sockets.  (these are omitted by default.)
-p, --program
       show the pid and name of the program to which each socket belongs.
--numeric , -n
show numerical addresses instead of trying to determine symbolic host, port or user names.

4、修改ssh的监听端口

（1）修改 /etc/ssh/sshd_config

原有的port 22

改为port 44

（2）重启服务

/etc/init.d/sshd restart
（3）查看情况

 netstat -tunl
active internet connections (only servers)
proto recv-q send-q local address    foreign address    state  
tcp  0  0 0.0.0.0:44    0.0.0.0:*     listen  
udp  0  0 ip:123   0.0.0.0:*        
udp  0  0 ip:123   0.0.0.0:*        
udp  0  0 127.0.0.1:123    0.0.0.0:*        
udp  0  0 0.0.0.0:123     0.0.0.0:*