ssh 접속 에러 - WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!

잘 접속하던 서버에 어느날 갑자기 뜬 에러 

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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:PUbdexxvgKNYkzTQdaqb6ufFA0tycIZEJnliWXpBFd8.
Please contact your system administrator.
Add correct host key in /var/root/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /var/root/.ssh/known_hosts:33
ECDSA host key for ec2-52-78-191-229.ap-northeast-2.compute.amazonaws.com has changed and you have requested strict checking.
Host key verification failed.

EC2 접근시 나왔던 에러인데, 다른 서버에서도 같은 상황에 비슷한 에러 발생 할 수 있을것 같다.

EC2의 경우에는 같은 아이피에 인스턴스를 바꾸게 되면 이와 같은 에러가 나온다고 한다. 

 

#해결방법 

1. sudo vi /var/root/.ssh/known_hosts 실행

2. 해당 파일 안의 접속이 불가한 아이피를 조회해서 삭제 후 저장

3. 다시 접속하면 깔끔하게 연결완료