ssh时出现@@@@@@@@

若在ssh ip时，出现

[root@stu22 ~]# ssh 172.16.1.28
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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
da:77:fc:e7:30:2d:28:cb:45:db:06:c2:24:74:4c:c0.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending key in /root/.ssh/known_hosts:1
RSA host key for 172.16.1.28 has changed and you have requested strict checking.
Host key verification failed.

则删除隐藏文件rm -rf .ssh

[root@stu22 ~]# rm -rf .ssh/