RSA host key has changed

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@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
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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
aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa.
Please contact your system administrator.
Add correct host key in /home/aaaaaaa/.ssh/known_hosts to get rid of this message.
Offending key in /home/aaaaaaa/.ssh/known_hosts:229
RSA host key for ad6 has changed and you have requested strict checking.
Host key verification failed.

方法1 : 删除 /home/aaaaaaa/.ssh/known_hosts 文件
优点:快
缺点:史上曾经登录的服务器再次登录还会再次需要 yes 同意.

方法2 : 删除 /home/aaaaaaa/.ssh/known_hosts 第229行
优点:只影响出问题的服务器
缺点:操作相对复杂

方法3 : ssh-keygen -R IP
操作优点,缺点均优于以上两点