本软件能实现在受到DDOS的cc、syn半连接等功击时，进行比较有效的防御。实际上，它并不具备阻截能力，它是基于IPtables防火墙，利用netstat+过滤规则，与IPtables防火墙实现联动。在有恶意连接（例如syn flood）攻击服务器指定端口时，本软件会实时分析连接来源的企图。当连接IP有多并发恶意连接时，软件自动将其加入iptables防火墙条目进行阻截。同时将攻击IP记录到计划解封文件里，当达到预定时间后，软件自动从IPtables防火墙中解封对应IP。

本软件利用了一周时间写完，在基本测试过程中，表现还可以。但不排除有BUG的可能。应付单IP并发连接攻击、单IP的syn flood等效果明显。由此可见，它也不适合于随机IP的恶意攻击。

系统结构图

安装使用：

本软件安装方式十分简单，下载软件后解压（tar zxvf DDos_firewall-v1.0.0.tar.gz），进入主目录，找到autosetup.sh，运行自动安装即可！

运行环境：

centos 32bit or 64bit 、redhat 32bit or 64bit、fedora 32bit or 64bit，其他linux未测试。

启动方式：

dd_start {start|stop|restart|status}

运行状态/IP封锁图

配置实例：

#############################################

### FileName:ddos_drop.conf

### Auth:Sunshine Gu

### http://blog.hit008.com

### ddos_acl and flush_drop config file.

#############################################

[main setting]

### Main directory

filepath=/usr/local/ddos_drop

### Pid file

ddos_acl_pidfile=/usr/local/ddos_drop/logs/ddos_acl.pid

flush_drop_pidfile=/usr/local/ddos_drop/logs/flush_drop.pid

### Temporary blacklist

grep_list=/usr/local/ddos_drop/logs/drop_ip.dat

### Plans to remove(blacklist)

crond_list=/usr/local/ddos_drop/logs/crond_list.dat

### Temporary file,used to clean blacklist queue in crond_list.

temp_list=/usr/local/ddos_drop/logs/temp_list~

### White list

else_list=192.168.14.15|127.0.0.1|0.0.0.0

### Monitor port

grep_port=80|8080|443

### Executive frequency(s)

exec_time=10

### Lock time,used to lock blacklist in grep_list,

### Over this time, iptables will automatically delete.(s)

acl_cls=3600

《Shell源码开源》

1. 主守护程序，ddos_acl.sh

#!/bin/sh

########################################

### FileName: ddos_acl.sh

### Auth: Sunshine GU

### Version: v1.0.0

### http://blog.hit008.com

########################################

############################################载入配置文件########################################

###文件主目录[filepath]

###PID文件[pidfile]

###临时黑名单[grep_list]

###计划清除队列[crond_list]

###白名单[else_list]

###监控端口[grep_port]

###执行频率(s) [exec_time]

conffile=../conf/ddos_drop.conf

if [ -e $conffile ];then

#cat $conffile|awk -v key="main" -v RS='\\[[^\n]*]' 'v=="["key"]";{v=RT}'|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'

filepath=`grep 'filepath=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

ddos_acl_pidfile=`grep 'ddos_acl_pidfile=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

flush_drop_pidfile=`grep 'flush_drop_pidfile=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

grep_list=`grep 'grep_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

crond_list=`grep 'crond_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

temp_list=`grep 'temp_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

else_list=`grep 'else_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

grep_port=`grep 'grep_port=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

exec_time=`grep 'exec_time=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

acl_cls=`grep 'acl_cls=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

else

echo "Can't find the configuration file!"

exit 1

fi

################################################################################################

###清空旧的非法IP

if [ -d $filepath/logs ];then

if [ -f $grep_list ];then

rm -f $grep_list

fi

else

mkdir $filepath/logs

fi

###根据连接状态进行IP屏蔽

echo "$$" > $ddos_acl_pidfile

while true

do

#根据连接数反应恶意连接,并记录连接ip

/bin/netstat -ant |grep -E $grep_port|awk '{print $5}'|awk -F : '{print $1}'|sort|uniq -c|sort -rn|grep -v -E $else_list|awk '{if ($2!=null && $1>100) {print $2}}' > $grep_list

if [ -f $grep_list ];then

#遍历不重复的条目

for i in `cat $grep_list|uniq -c|awk '{print $2}'`

do

#要求iptables没有重复条目

if [ `iptables --list|grep $i|wc -l` -eq 0 ];then

#记录非法IP信息,并进行封闭

echo "$i `date +%Y/%m/%d` `date +%H:%M:%S` `date +%s` LOCK" >> $crond_list

/sbin/iptables -I INPUT -s $i -j DROP;

else

continue

fi

done

fi

sleep $exec_time

done

2. 计划解封程序，flush_drop.sh

#!/bin/sh

########################################

### FileName: flush_drop.sh

### Auth: Sunshine GU

### Version: v1.0.0

### http://blog.hit008.com

########################################

############################################载入配置文件########################################

###文件主目录[filepath]

###PID文件[pidfile]

###临时黑名单[grep_list]

###计划清除队列[crond_list]

###白名单[else_list]

###监控端口[grep_port]

###执行频率(s) [exec_time]

conffile=../conf/ddos_drop.conf

if [ -e $conffile ];then

#cat $conffile|awk -v key="main" -v RS='\\[[^\n]*]' 'v=="["key"]";{v=RT}'|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'

filepath=`grep 'filepath=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

ddos_acl_pidfile=`grep 'ddos_acl_pidfile=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

flush_drop_pidfile=`grep 'flush_drop_pidfile=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

grep_list=`grep 'grep_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

crond_list=`grep 'crond_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

temp_list=`grep 'temp_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

else_list=`grep 'else_list=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

grep_port=`grep 'grep_port=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

exec_time=`grep 'exec_time=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

acl_cls=`grep 'acl_cls=' $conffile|sed 's/ //g'|sed -r '/^ *#.*/d;s/ *#.*//'|awk -F = '{print $2}'`

else

echo "Can't find the configuration file!"

exit 1

fi

################################################################################################

echo "$$" > $flush_drop_pidfile

while true

do

sleep $exec_time

#取得当前时间

nowtime=`date +%s`

#文件是否存在

if [ -e $crond_list ];then

#遍历所有条目

for i in `awk '{print $1}' $crond_list`

do

#内容不为空

if [ `cat $crond_list|wc -l` -ne 0 ];then

#单次最多取出一条,排除重复条目

ti=`grep $i $crond_list|awk '{print $4}'|head -1`

b=`expr $nowtime - $ti`

#判断是否超规定时间

if [ $b -gt $acl_cls ];then

#iptables里存在条目

if [ `iptables --list|grep $i|wc -l` -ne 0 ];then

/sbin/iptables -D INPUT -s $i -j DROP

fi

#清除crond_list的当前条目

cp $crond_list $temp_list

sed -e "/$i/d" $temp_list > $crond_list

rm -f $temp_list

fi

fi

done

fi

done

3. 主启动程序，dd_start.sh

#!/bin/sh

#############################################

### FileName:autosetup.sh

### Auth:Sunshine Gu

### Version: v1.0.0

### http://blog.hit008.com

### Bash shell for start DDos_Drop.

#############################################

### Main directory

filepath=/usr/local/ddos_drop

### Program name

DAEMON=$filepath/bin/ddos_acl

FLUSHIP=$filepath/bin/flush_drop

### Plans to remove(blacklist)

crond_list=$filepath/logs/crond_list.dat

### White list

else_list='127.0.0.1|0.0.0.0'

### Monitor port

grep_port='80|8080|443'

### Pid file

pidfile1=$filepath/logs/ddos_acl.pid

pidfile2=$filepath/logs/flush_drop.pid

set -e

[ -x "$DAEMON" ] || exit 0

do_start() {

if [ `pgrep -f 'ddos_acl'|wc -l` -eq 0 ];then

$DAEMON &

$FLUSHIP &

else

echo -e "ddos_acl already running!"

exit 1

fi

}

do_stop() {

if [ `pgrep -f 'ddos_acl'|wc -l` -eq 0 ];then

echo -e "ddos_acl not running!"

else

kill -9 `cat $pidfile1`

fi

if [ `pgrep -f 'flush_drop'|wc -l` -eq 0 ];then

echo -e "flush_drop not running!"

else

kill -9 `cat $pidfile2`

fi

if [ `pgrep -f 'flush_drop'|wc -l` -ne 0 ]&&[ `pgrep -f 'flush_acl'|wc -l` -ne 0 ];then

kill -9 `cat $pidfile1`

kill -9 `cat $pidfile2`

rm -rf $pidfile1 $pidfile2

fi

}

do_restart() {

do_stop

do_start

}

do_status() {

echo "###---------------------------DROP LIST----------------------------- ###"

echo "IP Y/m/d H:M:S Unix/time Active"

if [ -e $crond_list ];then

cat $crond_list

else

echo "no information..."

fi

echo "###---------------------------IPTABLES LIST--------------------------###"

echo "target prot opt source destination"

iptables --list|grep 'DROP'|awk {'printf "%-10s%-5s%-4s%-20s%-11s\n",$1,$2,$3,$4,$5'}

echo "###---------------------------NETSTAT STATUS-------------------------###"

echo "Num Proto Recv-Q Send-Q Local Address Foreign Address State"

netstat -ant |grep -E $grep_port|grep -v -E $else_list|sed 's/:/ /g'|awk '{print $1,$2,$3,$4,$6,$8}'|sort|uniq -c|awk '{printf "%-6s%-06s%-07s%-07s%-20s%-20s%-10s\n",$1,$2,$3,$4,$5,$6,$7}'

echo "###------------------------------------------------------------------###"

if [ `pgrep -f 'ddos_acl'|wc -l` -ne 0 ];then

echo -n ">>> ddos_acl already running! "

else

echo -n ">>> ddos_acl not running! "

fi

if [ `pgrep -f 'flush_drop'|wc -l` -ne 0 ];then

echo " flush_drop already running! <<<"

else

echo " flush_drop not running! <<<"

fi

}

case "$1" in

start)

echo -e "Starting ddos_acl ..."

do_start

echo "Done."

;;

stop)

echo -e "Stopping ddos_acl ..."

do_stop

echo "Done."

;;

restart)

echo -e "Restarting ddos_acl ..."

do_restart

echo "Done."

;;

status)

while true

do

clear

do_status

sleep 3

done

;;

*)

echo $"Usage: $prog {start|stop|restart|status}"

exit 1

esac

软件需安装到指定路径下（/usr/local/），安装好的目录有：

/usr/local/ddos_drop/bin，为执行文件目录

/usr/local/ddos_drop/conf，配置文件目录

/usr/local/ddos_drop/logs，记录文件目录

提供下载的为打包C文件，需要经过gcc编译。启动autosetup.sh 即可完成gcc编译和安装！

软件：DDos Firewall-v1.0.0

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