SSH 登录失败：Host key verification failed

如果某一个域名换了ip地址，比如hellotech.mobi,则ip地址切换之后，使用ssh登录时，如ssh root@hellotech.mobi，会提示异常。异常信息如下所示：

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@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @
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The ECDSA host key for hellotech.mobi has changed,
and the key for the corresponding IP address 47.188.63.90
is unchanged. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
Offending key for IP in /Users/aaron/.ssh/known_hosts:29
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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 ECDSA key sent by the remote host is
SHA256:MLmyflsdkjfalskflsdfjals928392QqqYCd0zFYM3JAFTG0cKE.
Please contact your system administrator.
Add correct host key in /Users/aaron/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/aaron/.ssh/known_hosts:24
ECDSA host key for hellotech.mobi has changed and you have requested strict checking.
Host key verification failed.

这个原因是由于公钥不一样了，所以无法登录，提示信息是 KEY 验证失败。解决方法很简单，就是将 /root/.ssh/known_hosts 文件里面的原来的公钥信息删除。切记不要删除整个文件。

known_hosts就是一个文本文件，里面记录了本地所有ssh登录过的域名，ip。文件按行区分，每行一个域名或ip。