ssh登录失败，WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!

# ssh 192.168.210.163
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@    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
db:79:18:e8:7b:3d:b3:55:0b:32:13:19:e8:57:ea:5f.
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 192.168.210.163 has changed and you have requested strict checking.
Host key verification failed.

ssh会把每个访问过的机器的公钥记录在 ~/.ssh/known_hosts中，下次登录时OPENSSH会核对该公钥，如果服务器公钥改变，便会给出上面提示

输入如下命令释放：

# ssh-keygen -R 192.168.210.163