同じIPアドレスでサーバを用意した場合、SSHで接続するときに下記のようなエラーがせることがある
$ ssh root@123.123.123.123
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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 a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
9a:33:31:63:13:85:d3:32:c1:bb:d9:0f:cc:d9:c5:f6.
Please contact your system administrator.
Add correct host key in /Users/hideaki/.ssh/known_hosts to get rid of this message.
Offending RSA key in /Users/hideaki/.ssh/known_hosts:51
Password authentication is disabled to avoid man-in-the-middle attacks.
Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.
Permission denied (publickey,password,keyboard-interactive).
解決方法
$ ssh-keygen -R 123.123.123.123
↓
再度接続！