使用PT-Accelerator的 清空Hosts文件并更新Hosts 导致拒绝服务
会清空hosts文件导致nginx启动失败
使用ssh连接，手动在hosts中添加
127.0.0.1 localhost
127.0.1.1 trim
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
重启后解决
