linux httpd备忘

1.查看dos攻击，看一下SYN_RECV是否很高
    netstat -an|grep -i "192.168.32.24:80"| awk '{print $6}' | sort | uniq -c | sort -n
解决方法：echo 1 > /proc/sys/net/ipv4/tcp_syncookies
2.ulimit -a查看文件数，解决java.net.SocketException: Too many open files异常