今天連線linux時居然連不上，報錯資訊是：

Connecting to 192.168.16.133:22...
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.

Connection closed by foreign host.

Disconnected from remote host(hadoop3) at 10:56:11.

Type `help' to learn how to use Xshell prompt.

    cd /etc/ssh
    sudo chmod 644 ./*
    sudo chmod 600 ssh_host_dsa_key
    sudo chmod 600 ssh_host_rsa_key
    sudo chmod 755 .
    /etc/init.d/sshd restart