Connection closing...Socket close. Connection closed by foreign host. Disconnected from remote host(centos6.9) at 14:59:05.

查找網上資料解決方法如下

[root@localhost ssh]# service sshd start
Starting sshd: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0622 for '/etc/ssh/ssh_host_rsa_key' are too open.#密鑰文件權限不能為0644,0644權限太開放了，要求你的密鑰文件不能被其它用戶讀取
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /etc/ssh/ssh_host_rsa_key
Could not load host key: /etc/ssh/ssh_host_rsa_key
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0622 for '/etc/ssh/ssh_host_dsa_key' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /etc/ssh/ssh_host_dsa_key
Could not load host key: /etc/ssh/ssh_host_dsa_key
/var/empty/sshd must be owned by root and not group or world-writable.
                                                           [FAILED]
[root@localhost ssh]# chmod 700 /etc/ssh/ssh_host_rsa_key #修改一下密鑰文件權限。
[root@localhost ssh]# service ssh restart
ssh: unrecognized service
[root@localhost ssh]# /etc/init.d/sshd restart
Stopping sshd:                                             [FAILED]
Starting sshd: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0622 for '/etc/ssh/ssh_host_dsa_key' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /etc/ssh/ssh_host_dsa_key
Could not load host key: /etc/ssh/ssh_host_dsa_key
/var/empty/sshd must be owned by root and not group or world-writable.
                                                           [FAILED]
[root@localhost ssh]# chmod 700 ssh_host_rsa_key
[root@localhost ssh]# chmod 700 ssh_host_dsa_key
[root@localhost ssh]# service sshd restart
Stopping sshd:                                             [FAILED]
Starting sshd: /var/empty/sshd must be owned by root and not group or world-writable.#也是權限的問題
                                                           [FAILED]
[root@localhost ssh]# vim sshd_config
[root@localhost ssh]# chown -R root.root /var/empty/sshd
[root@localhost ssh]# chmod 744 /var/empty/sshd
[root@localhost ssh]# service sshd restart
Stopping sshd:                                             [FAILED]
Starting sshd:                                             [  OK  ]