tcpdump -s0 -A -n -i any | grep ^User-Agent
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; 360space)
这个是查看客户端的useragent,正常的结果中,是各种各样的useragent。
大多数攻击使用的是固定的useragent,也就是会看到同一个useragent在刷屏。随机的useragent只见过一次,但是给搞成了类似于这样“axd5m8usy”,还是可以分辨出来。
第三条命令:
tcpdump -s0 -A -n -i any | grep ^Host
如果机器上的网站太多,可以用上面的命令找出是哪个网站在被大量请求
输出结果类似于下面这样
Host: www.server110.com
Host: www.server110.com
Host: www.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: upload.server110.com
Host: www.server110.com
Host: upload.server110.com
一般系统不会默认安装tcpdump命令
centos安装方法:yum install -y tcpdump
debian/ubuntu安装方法:apt-get install -y tcpdump