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为什么我无法连接到新的 Ubuntu 服务器？

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为什么我无法连接到新的 Ubuntu 服务器？ 
I'm trying to connect to a new Ubuntu server. I was using the hardware of this server previously (with Desktop Ubuntu) before installing Ubuntu server. Do you know what can be happening?

    Bernardos-MacBook-Pro:~ bernardo$ ssh [email protected]
    @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    @    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 a host key has just been changed.
    The fingerprint for the ECDSA key sent by the remote host is
    SHA256:4cTDTZMivYKNPugdQQlwGDKcV6FvnSTsY7jAf0hW7Q0.
    Please contact your system administrator.
    Add correct host key in /Users/bernardo/.ssh/known_hosts to get rid of this message.
    Offending ECDSA key in /Users/bernardo/.ssh/known_hosts:28
    ECDSA host key for 192.168.1.43 has changed and you have requested strict checking.
    Host key verification failed.

    Bernardos-MacBook-Pro:~ bernardo$ ssh-keygen -R 192.168.1.123
    Host 192.168.1.123 not found in /Users/bernardo/.ssh/known_hosts

    Bernardos-MacBook-Pro:~ bernardo$ sed -i '28d' ~/.ssh/known_hosts
    sed: 1: "/Users/bernardo/.ssh/kn ...": undefined label     'ernardo/.ssh/known_hosts'

手动删除第 28 行后

        Bernardos-MacBook-Pro:~ bernardo$ ssh [email protected]
        The authenticity of host '192.168.1.43 (192.168.1.43)' can't be established.
        ECDSA key fingerprint is SHA256:4cTDTZMivYKNPugdQQlwGDKcV6FvnSTsY7jAf0hW7Q0.

        Are you sure you want to continue connecting (yes/no)? yes

        Warning: Permanently added '192.168.1.43' (ECDSA) to the list of known hosts.

        Permission denied (publickey).

答案1

安装sshd将自动安装主机密钥。连接到主机时，客户端将检查它是否已经拥有您尝试连接的主机的密钥。如果没有，它会询问您是否可以安全连接到该主机。如果有，并且与之前相同，它不会询问任何问题。但是如果它已经有密钥并且它是不同的，它知道它没有连接到它之前连接的同一个操作系统安装，并且它假设出了问题。在这种情况下，您重新安装了操作系统而没有费心保存并重新安装以前的主机密钥，但您的 SSH 客户端不知道，其他人可能正在尝试冒充您的主机。

要消除此错误，请从您的

~/.ssh/known_hosts

至于为什么不能用命令删除该行sed，我同意@user1700494 的理论；用来man sed看看你的sed支持是什么。

答案2

我不用 OS X，但我知道 OS Xsed不是 GNU sed。我猜你sed不理解-i密钥。你需要手动删除第 28 行的条目/Users/bernardo/.ssh/known_hosts或安装gnu-sed

答案3

Please contact your system administrator.
Add correct host key in /Users/bernardo/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/bernardo/.ssh/known_hosts:28

您手动完成此操作并得到：

Permission denied (publickey)

听起来您需要在服务器上启用基于密码的登录，或者将您的公钥添加到authorized_users服务器上的文件中。

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