：使用SSH遠端連線Linux系統的ECS執行個體時，提示“Host key verification failed”錯誤怎麼辦？

問題現象

• 本地用戶端為Linux環境或macOS環境，使用SSH方式無法正常串連Linux系統的ECS執行個體時，提示如下錯誤資訊。

  @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  @ 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
  ae:6e:68:4c:97:a6:91:81:11:38:8d:64:ff:92:13:50.
  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:70
  RSA host key for x.x.x.x has changed and you have requested strict checking.
  Host key verification failed.

• 本地用戶端為Windows環境，使用常見的SSH用戶端（如Putty或MobaXterm）串連Linux系統的ECS執行個體時，提示類似“The host key does not match the one Putty has cached for this server”或“remote server identification has changed”錯誤資訊。

  PuTTY 彈出 WARNING - POTENTIAL SECURITY BREACH! 安全警告對話方塊，密鑰類型為 ssh-ed25519，使用者可單擊 Accept、Connect Once 或 Cancel 按鈕進行響應。

  MobaXterm的警告對話方塊提供三個操作按鈕：Accept the new server hostkey and carry on connecting、Refuse the new server hostkey and abort the connection 和 Accept and save as additional hostkey (keep the existing ones)。

問題原因

該ECS執行個體可能進行過重裝系統、賬戶資訊變更等操作，導致ECS執行個體SSH公開金鑰變更，造成本地用戶端儲存的公開金鑰指紋與伺服器端不一致，出現該提示資訊。

解決方案

您可以根據本地用戶端環境不同，選擇合適的方案。