SSH登陸錯誤解決辦法：
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
21:24:59:ba:53:d7:51:a2:12:13:40:09:53:03:5b:e6.
Please contact your system administrator.
Add correct host key in /home/cmccpay/.ssh/known_hosts to get rid of this message.
Offending key in /home/cmccpay/.ssh/known_hosts:11
RSA host key for 10.202.76.27 has changed and you have requested strict checking.
Host key verification failed.
出現該錯誤的解決方法：
- 因為在本地機器上曾經用SSH登錄過這台遠程計算機，因而留下了known_hosts的記錄，在遠程計算機重新安裝系統后不能夠通過鑒權。刪除~/.ssh/known_hosts中對應的項目，問題獲得解決。（很麻煩。。忽視之）
- 在客戶端執行下述指令即可：$mv ~/.ssh/known_hosts /tmp （相對好一點，用過）
再次登錄后會出現最初需要增加條目：
The authenticity of host '128.112.139.3 (128.112.139.3)' can't be established.
RSA key fingerprint is ce:78:c2:d5:26:11:42:cf:c6:e6:65:99:9c:60:51:34.
Are you sure you want to continue connecting (yes/no)? The authenticity of host '132.170.3.32 (132.170.3.32)' can't be established.
RSA key fingerprint is 91:14:9c:ea:e7:43:5d:8b:57:aa:51:57:e0:28:06:52.
Are you sure you want to continue connecting (yes/no)? yes - 配置文件進行配置，使出現“Warning: Host identification has changed!”時候可以自動更新~/.ssh/known_hosts中的相應條目，而不出現提示。（比較好！方便，無需后期處理）
OpenSSH 有三種配置方式：命令行參數、用戶配置文件和系統級的配置文件（"/etc/ssh/ssh_config"）。命令行參數優先於配置文件，用戶配置文件優先於系統配置文件。所有的命令行的參數都能在配置文件中設置。因為在安裝的時候沒有默認的用戶配置文件，所以要把"/etc/ssh /ssh_config"拷貝並重新命名為"~/.ssh/config"。
（下一篇中具體介紹ssh的配置文件）
注意在配置文件~/.ssh/config中修改下面的內容：
Host *
GSSAPIAuthentication yes
BatchMode yes
StrictHostKeyChecking no