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此脚本包含的功能有：
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。
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#!/bin/bash #显示菜单(单选)display_menu(){local soft=$1local prompt="which ${soft} you‘d select: "eval local arr=(\${${soft}_arr[@]})while truedo echo -e "#################### ${soft} setting ####################\n\n" for ((i=1;i<=${#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 fidone} #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 "\033[0;0H" #清屏并打印Now Peak [[ $clear == true ]] && printf "\033[2J" && echo "$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 "\033[2;1H" #清除当前行 printf "\033[K" printf "%-20s %-20s\n" "Receive: $(bit_to_human_readable $eth_in)" "$(bit_to_human_readable $eth_in_peak)" #清除当前行 printf "\033[K" printf "%-20s %-20s\n" "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 $2}‘` #处理tcpdump文件 awk ‘/^IP/{print;getline;print}‘ /tmp/tcpdump_temp > /tmp/tcpdump_temp2 awk ‘{len=$NF;sub(/\)/,"",len);getline;print $0,len}‘ /tmp/tcpdump_temp2 > /tmp/tcpdump #10s后流量值 local traffic_af=(`awk -v eth=$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 "\033[32mnetwork device $eth average traffic in 10s: \033[0m" echo "$eth Receive: $(bit_to_human_readable $eth_in)/s" echo "$eth Transmit: $(bit_to_human_readable $eth_out)/s" echo #统计每个端口在10s内的平均流量 regTcpdump=$(ifconfig | grep -A 1 $eth | awk -F‘[: ]+‘ ‘$0~/inet addr:/{printf $4"|"}‘ | sed -e ‘s/|$//‘ -e ‘s/^/(/‘ -e ‘s/$/)\\\\\.[0-9]+:/‘) echo -e "\033[32maverage traffic in 10s base on server port: \033[0m" awk -F‘[ .:]+‘ -v regTcpdump=$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 %d\n",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 $d)/s" done echo echo -e "\033[32maverage traffic in 10s base on client port: \033[0m" awk -F‘[ .:]+‘ -v regTcpdump=$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 %d\n",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 $d)/s" done echo #统计在10s内占用带宽最大的前10个ip echo -e "\033[32mtop 10 ip average traffic in 10s : \033[0m" awk -F‘[ .:]+‘ -v regTcpdump=$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 %d\n",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 $d)/s" done echo #统计连接状态 regSS=$(ifconfig | grep -A 1 $eth | awk -F‘[: ]+‘ ‘$0~/inet addr:/{printf $4"|"}‘ | sed -e ‘s/|$//‘) ss -an | grep -v -E "LISTEN|UNCONN" | grep -E "$regSS" > /tmp/ss echo -e "\033[32mconnection state count: \033[0m" awk ‘NR>1{sum[$(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 "\033[32mconnection state count by port: \033[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 #统计端口为80且状态为ESTAB连接数最多的前10个IP echo -e "\033[32mtop 10 ip ESTAB state count at port 80: \033[0m" cat /tmp/ss | grep ESTAB | awk -F‘[: ]+‘ ‘{sum[$(NF-2)]+=1}END{for (ip in sum){print ip,sum[ip]}}‘ | sort -k 2 -nr | head -n 10 echo #统计端口为80且状态为SYN-RECV连接数最多的前10个IP echo -e "\033[32mtop 10 ip SYN-RECV state count at port 80: \033[0m" cat /tmp/ss | grep -E "$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 |
转载：http://jin771998569.blog.51cto.com/2147853/1587726
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原文地址：http://www.cnblogs.com/diyunpeng/p/4606414.html
