SSH连接的时候遇到错误提示：

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @
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 XXXXXXX Please contact your
system administrator. Add correct host key in
/home/conbar/.ssh/known_hosts to get rid of this message. Offending
key in /home/kaifage.com/.ssh/known_hosts:10 RSA host key for
XXXXXXXXX has changed and you have requested strict checking. Host key
verification failed.

可能是『中间人攻击』，也可能是RSA host key改变。实际情况是server重装了一次系统，原先ssh客户端存储的RSA认证已经失效了。

解决：

ssh-keygen -R IP地址