介绍一个强大的分析网络的shell脚本,此脚本是从EZHTTP拆分出来的,觉得有必要单独介绍下。
脚本运行效果截图:
- 1、实时监控任意网卡的流量
- 2、统计10秒内平均流量
- 3、统计每个端口在10秒内的平均流量,基于客户端和服务端端口统计。可以看出哪些端口占流量比较大,对于web服务器,一般是80端口。其它端口受到攻击时,也有可能其它端口流量比较大。所以此功能可以帮助我们端口流量是否正常。
- 4、统计在10s内占用带宽最大的前10个ip。此项功能可以帮助我们来查出是否有恶意占用带宽的ip。
- 5、统计连接状态。此项功能可以让我们看出哪些连接状态比较大。如果SYN-RECV状态比较多的话,有可以受到半连接攻击。如果ESTABLISED非常大,但通过日志发现没有那么多请求,或者通过tcpdump发现大量ip只建立连接不请求数据的话,可能是受到了全连接攻击,这时候如果你使用的是nginx服务器,可以在配置文件增加listen 80 deferred来防止。
- 6、统计各端口连接状态。当可能受到攻击时,此项功能可以帮助我们发现是哪个端口受到攻击。
- 7、统计端口为80且状态为ESTAB连接数最多的前10个IP。此项功能可以帮助我们来找出创建连接过多的Ip,进而屏蔽。
- 8、统计端口为80且状态为SYN-RECV连接数最多的前10个IP。当受到半连接攻击时,此项功能可以帮助我们找到恶意ip。
用到的网络分析工具:
- 1、tcpdump:此脚本用tcpdump来统计基于ip或基于端口的流量。
- 2、ss: 此脚本用ss命令来统计连接状态,实际使用发现ss比netstat高效得多。
- 3、/proc/net/dev,用来统计指定网卡的流量。
脚本下载地址:http://devops.webres.wang/wp-content/uploads/2014/06/network-analysis.sh
下面贴出完整的脚本:
- #!/bin/bash
- #write by zhumaohai(admin#webres.wang)
- #author blog: devops.webres.wang
- #显示菜单(单选)
- display_menu(){
- local soft=$1
- local prompt="which ${soft} you’d select: "
- eval local arr=(${${soft}_arr[@]})
- while true
- do
- echo -e "#################### ${soft} setting ####################nn"
- for ((i=1;i<=${#arr[@]};i++ )); do echo -e "$i) ${arr[$i-1]}"; done
- echo
- read -p "${prompt}" $soft
- eval local select=$$soft
- if [ "$select" == "" ] || [ "${arr[$soft-1]}" == "" ];then
- prompt="input errors,please input a number: "
- else
- eval $soft=${arr[$soft-1]}
- eval echo "your selection: $$soft"
- break
- fi
- done
- }
- #把带宽bit单位转换为人类可读单位
- bit_to_human_readable(){
- #input bit value
- local trafficValue=$1
- if [[ ${trafficValue%.*} -gt 922 ]];then
- #conv to Kb
- trafficValue=`awk -v value=$trafficValue ‘BEGIN{printf "%0.1f",value/1024}’`
- if [[ ${trafficValue%.*} -gt 922 ]];then
- #conv to Mb
- trafficValue=`awk -v value=$trafficValue ‘BEGIN{printf "%0.1f",value/1024}’`
- echo "${trafficValue}Mb"
- else
- echo "${trafficValue}Kb"
- fi
- else
- echo "${trafficValue}b"
- fi
- }
- #判断包管理工具
- check_package_manager(){
- local manager=$1
- local systemPackage=”
- if cat /etc/issue | grep -q -E -i "ubuntu|debian";then
- systemPackage=’apt’
- elif cat /etc/issue | grep -q -E -i "centos|red hat|redhat";then
- systemPackage=’yum’
- elif cat /proc/version | grep -q -E -i "ubuntu|debian";then
- systemPackage=’apt’
- elif cat /proc/version | grep -q -E -i "centos|red hat|redhat";then
- systemPackage=’yum’
- else
- echo "unkonw"
- fi
- if [ "$manager" == "$systemPackage" ];then
- return 0
- else
- return 1
- fi
- }
- #实时流量
- realTimeTraffic(){
- local eth=""
- local nic_arr=(`ifconfig | grep -E -o "^[a-z0-9]+" | grep -v "lo" | uniq`)
- local nicLen=${#nic_arr[@]}
- if [[ $nicLen -eq 0 ]]; then
- echo "sorry,I can not detect any network device,please report this issue to author."
- exit 1
- elif [[ $nicLen -eq 1 ]]; then
- eth=$nic_arr
- else
- display_menu nic
- eth=$nic
- fi
- local clear=true
- local eth_in_peak=0
- local eth_out_peak=0
- local eth_in=0
- local eth_out=0
- while true;do
- #移动光标到0:0位置
- printf "33[0;0H"
- #清屏并打印Now Peak
- [[ $clear == true ]] && printf "33[2J" && echo "$eth——–Now——–Peak———–"
- traffic_be=(`awk -v eth=$eth -F'[: ]+’ ‘{if ($0 ~eth){print $3,$11}}’ /proc/net/dev`)
- sleep 2
- traffic_af=(`awk -v eth=$eth -F'[: ]+’ ‘{if ($0 ~eth){print $3,$11}}’ /proc/net/dev`)
- #计算速率
- eth_in=$(( (${traffic_af[0]}-${traffic_be[0]})*8/2 ))
- eth_out=$(( (${traffic_af[1]}-${traffic_be[1]})*8/2 ))
- #计算流量峰值
- [[ $eth_in -gt $eth_in_peak ]] && eth_in_peak=$eth_in
- [[ $eth_out -gt $eth_out_peak ]] && eth_out_peak=$eth_out
- #移动光标到2:1
- printf "33[2;1H"
- #清除当前行
- printf "33[K"
- printf "%-20s %-20sn" "Receive: $(bit_to_human_readable $eth_in)" "$(bit_to_human_readable $eth_in_peak)"
- #清除当前行
- printf "33[K"
- printf "%-20s %-20sn" "Transmit: $(bit_to_human_readable $eth_out)" "$(bit_to_human_readable $eth_out_peak)"
- [[ $clear == true ]] && clear=false
- done
- }
- #流量和连接概览
- trafficAndConnectionOverview(){
- if ! which tcpdump > /dev/null;then
- echo "tcpdump not found,going to install it."
- if check_package_manager apt;then
- apt-get -y install tcpdump
- elif check_package_manager yum;then
- yum -y install tcpdump
- fi
- fi
- local reg=""
- local eth=""
- local nic_arr=(`ifconfig | grep -E -o "^[a-z0-9]+" | grep -v "lo" | uniq`)
- local nicLen=${#nic_arr[@]}
- if [[ $nicLen -eq 0 ]]; then
- echo "sorry,I can not detect any network device,please report this issue to author."
- exit 1
- elif [[ $nicLen -eq 1 ]]; then
- eth=$nic_arr
- else
- display_menu nic
- eth=$nic
- fi
- echo "please wait for 10s to generate network data…"
- echo
- #当前流量值
- local traffic_be=(`awk -v eth=$eth -F'[: ]+’ ‘{if ($0 ~eth){print $3,$11}}’ /proc/net/dev`)
- #tcpdump监听网络
- tcpdump -v -i $eth -tnn > /tmp/tcpdump_temp 2>&1 &
- sleep 10
- clear
- kill `ps aux | grep tcpdump | grep -v grep | awk ‘{print $2}’`
- #10s后流量值
- local traffic_af=(`awk -v eth=$eth -F'[: ]+’ ‘{if ($0 ~eth){print $3,$11}}’ /proc/net/dev`)
- #打印10s平均速率
- local eth_in=$(( (${traffic_af[0]}-${traffic_be[0]})*8/10 ))
- local eth_out=$(( (${traffic_af[1]}-${traffic_be[1]})*8/10 ))
- echo -e "33[32mnetwork device $eth average traffic in 10s: 33[0m"
- echo "$eth Receive: $(bit_to_human_readable $eth_in)/s"
- echo "$eth Transmit: $(bit_to_human_readable $eth_out)/s"
- echo
- local regTcpdump=$(ifconfig | grep -A 1 $eth | awk -F'[: ]+’ ‘$0~/inet addr:/{printf $4"|"}’ | sed -e ‘s/|$//’ -e ‘s/^/(/’ -e ‘s/$/)\\.[0-9]+:/’)
- #新旧版本tcpdump输出格式不一样,分别处理
- if awk ‘/^IP/{print;exit}’ /tmp/tcpdump_temp | grep -q ")$";then
- #处理tcpdump文件
- awk ‘/^IP/{print;getline;print}’ /tmp/tcpdump_temp > /tmp/tcpdump_temp2
- else
- #处理tcpdump文件
- awk ‘/^IP/{print}’ /tmp/tcpdump_temp > /tmp/tcpdump_temp2
- sed -i -r ‘s#(.*: [0-9]+))(.*)#1n 2#’ /tmp/tcpdump_temp2
- fi
- awk ‘{len=$NF;sub(/)/,"",len);getline;print $0,len}’ /tmp/tcpdump_temp2 > /tmp/tcpdump
- #统计每个端口在10s内的平均流量
- echo -e "33[32maverage traffic in 10s base on server port: 33[0m"
- awk -F'[ .:]+’ -v regTcpdump=$regTcpdump ‘{if ($0 ~ regTcpdump){line="clients > "$8"."$9"."$10"."$11":"$12}else{line=$2"."$3"."$4"."$5":"$6" > clients"};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}’ /tmp/tcpdump |
- sort -k 4 -nr | head -n 10 | while read a b c d;do
- echo "$a $b $c $(bit_to_human_readable $d)/s"
- done
- echo -ne "33[11A"
- echo -ne "33[50C"
- echo -e "33[32maverage traffic in 10s base on client port: 33[0m"
- awk -F'[ .:]+’ -v regTcpdump=$regTcpdump ‘{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5":"$6" > server"}else{line="server > "$8"."$9"."$10"."$11":"$12};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}’ /tmp/tcpdump |
- sort -k 4 -nr | head -n 10 | while read a b c d;do
- echo -ne "33[50C"
- echo "$a $b $c $(bit_to_human_readable $d)/s"
- done
- echo
- #统计在10s内占用带宽最大的前10个ip
- echo -e "33[32mtop 10 ip average traffic in 10s base on server: 33[0m"
- awk -F'[ .:]+’ -v regTcpdump=$regTcpdump ‘{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5" > "$8"."$9"."$10"."$11":"$12}else{line=$2"."$3"."$4"."$5":"$6" > "$8"."$9"."$10"."$11};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}’ /tmp/tcpdump |
- sort -k 4 -nr | head -n 10 | while read a b c d;do
- echo "$a $b $c $(bit_to_human_readable $d)/s"
- done
- echo -ne "33[11A"
- echo -ne "33[50C"
- echo -e "33[32mtop 10 ip average traffic in 10s base on client: 33[0m"
- awk -F'[ .:]+’ -v regTcpdump=$regTcpdump ‘{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5":"$6" > "$8"."$9"."$10"."$11}else{line=$2"."$3"."$4"."$5" > "$8"."$9"."$10"."$11":"$12};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}’ /tmp/tcpdump |
- sort -k 4 -nr | head -n 10 | while read a b c d;do
- echo -ne "33[50C"
- echo "$a $b $c $(bit_to_human_readable $d)/s"
- done
- echo
- #统计连接状态
- local regSS=$(ifconfig | grep -A 1 $eth | awk -F'[: ]+’ ‘$0~/inet addr:/{printf $4"|"}’ | sed -e ‘s/|$//’)
- ss -an | grep -v -E "LISTEN|UNCONN" | grep -E "$regSS" > /tmp/ss
- echo -e "33[32mconnection state count: 33[0m"
- awk ‘NR>1{sum[$(NF-4)]+=1}END{for (state in sum){print state,sum[state]}}’ /tmp/ss | sort -k 2 -nr
- echo
- #统计各端口连接状态
- echo -e "33[32mconnection state count by port base on server: 33[0m"
- awk ‘NR>1{sum[$(NF-4),$(NF-1)]+=1}END{for (key in sum){split(key,subkey,SUBSEP);print subkey[1],subkey[2],sum[subkey[1],subkey[2]]}}’ /tmp/ss | sort -k 3 -nr | head -n 10
- echo -ne "33[11A"
- echo -ne "33[50C"
- echo -e "33[32mconnection state count by port base on client: 33[0m"
- awk ‘NR>1{sum[$(NF-4),$(NF)]+=1}END{for (key in sum){split(key,subkey,SUBSEP);print subkey[1],subkey[2],sum[subkey[1],subkey[2]]}}’ /tmp/ss | sort -k 3 -nr | head -n 10 | awk ‘{print "33[50C"$0}’
- echo
- #统计端口为80且状态为ESTAB连接数最多的前10个IP
- echo -e "33[32mtop 10 ip ESTAB state count at port 80: 33[0m"
- cat /tmp/ss | grep ESTAB | awk -F'[: ]+’ ‘{sum[$(NF-2)]+=1}END{for (ip in sum){print ip,sum[ip]}}’ | sort -k 2 -nr | head -n 10
- echo
- #统计端口为80且状态为SYN-RECV连接数最多的前10个IP
- echo -e "33[32mtop 10 ip SYN-RECV state count at port 80: 33[0m"
- cat /tmp/ss | grep -E "$regSS" | grep SYN-RECV | awk -F'[: ]+’ ‘{sum[$(NF-2)]+=1}END{for (ip in sum){print ip,sum[ip]}}’ | sort -k 2 -nr | head -n 10
- }
- main(){
- while true; do
- echo -e "1) real time traffic.n2) traffic and connection overview.n"
- read -p "please input your select(ie 1): " select
- case $select in
- 1) realTimeTraffic;break;;
- 2) trafficAndConnectionOverview;break;;
- *) echo "input error,please input a number.";;
- esac
- done
- }
- main
脚本中如有不明白的地方,可以留言咨询。