用xshell连接linux服务器出现以下错误

用xshell连接linux服务器出现以下错误

Connecting to 192.168.3.15:22...

Connection established.

To escape to local shell, press 'Ctrl+Alt+]'.

Socket error Event: 32 Error: 10053.

Connection closing...Socket close.

Connection closed by foreign host.

Disconnected from remote host(192.168.3.15:22) at 20:00:30.

原因：
改变了系统权限 chmod 777 -R

解决方案：

#chmod 400 /etc/ssh/*