1. 问题：ssh 连接服务器出现以下报错

(base) Robin-macbook-pro:~ robin$  ssh suer@192.168.21.212
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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:IIFv8zvHN4axw3d3WOmTZ6UtzqY1e8JYD0xGlmRehY8.
Please contact your system administrator.
Add correct host key in /Users/robin/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/robin/.ssh/known_hosts:2
ECDSA host key for 192.168.21.212 has changed and you have requested strict checking.
Host key verification failed.

2. 原因：服务器重新安装系统

第一次使用SSH连接时，会生成一个认证，储存在客户端的known_hosts中。

可使用以下指令查看：ssh-keygen -l -f ~/.ssh/known_hosts

由于服务器重新安装系统了，所以会出错。

此报错是由于远程的主机的公钥发生了变化导致的。
ssh服务是通过公钥和私钥来进行连接的，它会把每个曾经访问过计算机或服务器的公钥（public key），记录在~/.ssh/known_hosts 中，当下次访问曾经访问过的计算机或服务器时，ssh就会核对公钥，如果和上次记录的不同，OpenSSH会发出警告。

3. 解决：清除连接

使用命令清除所连接的IP：ssh-keygen -R 服务器端的ip地址

重新连线,出现以下提示：

输入yes确认即可连线成功。

输入密码后的确是登陆成功了，但是不一会就断了：

一下子就自动断开了：

suer@allinone-zxzx:~$ packet_write_wait: Connection to 192.168.21.212 port 22: Broken pipe

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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:aXtiQYKlJauqeoKilM+ZzMd1rTkSCN2PHh7QY6Plqh0.
Please contact your system administrator.
Add correct host key in /Users/robin/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/robin/.ssh/known_hosts:2
ECDSA host key for 192.168.21.212 has changed and you have requested strict checking.
Host key verification failed.

4. 再次解决：删除公钥

根据提示：Add correct host key in /Users/robin/.ssh/known_hosts to get rid of this message.
将known_hosts文件中的与登录错误的IP的公钥删除：

• 进入：vim /Users/robin/.ssh/known_hosts
• 删掉对应的那条公钥
• 重新连接和登陆

• 成功登陆！

参考：

1. REMOTE HOST IDENTIFICATION HAS CHANGED问题解决
2. Linux使用ssh远程连接服务器异常修复