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Today I check my Gmail, and found a email from Digital Ocean, warned me that the server owned by me was attacking another server.

So I want to find out what the problem is, and the tools I used is

  1. tcpdump
  2. netstat
  3. wireshark

tcpdump -i eth0 -vvv -X   host
tcpdump -i eth0 -vvv -X not  host

netstat -anp

tcpdump tcp -i eth1 -t -s 0 -c 100 and dst port ! 22 and src net -w ./target.cap

(1)tcp: ip icmp arp rarp 和 tcp、udp、icmp这些选项等都要放到第一个参数的位置,用来过滤数据报的类型
(2)-i eth1 : 只抓经过接口eth1的包
(3)-t : 不显示时间戳
(4)-s 0 : 抓取数据包时默认抓取长度为68字节。加上-S 0 后可以抓到完整的数据包
(5)-c 100 : 只抓取100个数据包
(6)dst port ! 22 : 不抓取目标端口是22的数据包
(7)src net : 数据包的源网络地址为192.168.1.0/24
(8)-w ./target.cap : 保存成cap文件,方便用ethereal(即wireshark)分析

/var/www/dokuwiki/wiki/data/pages/linux/tcpdump.txt · Last modified: 2016/05/05 13:07 by