问题

如题目所示

报错如下：

 systemctl status sshd
● ssh.service - OpenBSD Secure Shell server
   Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab
   Active: active (running) since Thu 2025-06-19 14:12:42 CST; 2h 7min ago
  Process: 48523 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
 Main PID: 48524 (sshd)
    Tasks: 1 (limit: 4591)
   CGroup: /system.slice/ssh.service
           └─48524 /usr/sbin/sshd -D

6月 19 16:14:44 ubuntu sshd[53013]: error: Could not load host key: /etc/ssh/ssh
6月 19 16:14:44 ubuntu sshd[53013]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
6月 19 16:14:44 ubuntu sshd[53013]: error: @         WARNING: UNPROTECTED PRIVAT
6月 19 16:14:44 ubuntu sshd[53013]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
6月 19 16:14:44 ubuntu sshd[53013]: error: Permissions 0777 for '/etc/ssh/ssh_ho
6月 19 16:14:44 ubuntu sshd[53013]: error: It is required that your private key 
6月 19 16:14:44 ubuntu sshd[53013]: error: This private key will be ignored.
6月 19 16:14:44 ubuntu sshd[53013]: error: key_load_private: bad permissions
6月 19 16:14:44 ubuntu sshd[53013]: error: Could not load host key: /etc/ssh/ssh
6月 19 16:14:44 ubuntu sshd[53013]: fatal: No supported key exchange algorithms 

原因

ssh密钥发生了改变

解决办法

分为ubuntu和主机两个方面,(sudo apt-get remove 然后install 的方法没有效果)

1.ubuntu

重新生成密钥

$ ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
Generating public/private rsa key pair.
/etc/ssh/ssh_host_rsa_key already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /etc/ssh/ssh_host_rsa_key.
Your public key has been saved in /etc/ssh/ssh_host_rsa_key.pub.
The key fingerprint is:
SHA256:q0Qz+dqDtBIFX79tbV0iRrIIfIyxUTsgx6wLjaGN0eg zghy@ubuntu
The key's randomart image is:
+---[RSA 2048]----+
| o  .+==.        |
|o o .o*++.. .    |
|.= + +.+oo +     |
|oE+ o o...o o . .|
|   . o= S  + o o.|
|    o..+ .. o o .|
|     o.oo  . .   |
|    ..o+.        |
|     .o ..       |
+----[SHA256]-----+

接着执行

$ ssh-keygen -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key
Generating public/private ecdsa key pair.
/etc/ssh/ssh_host_ecdsa_key already exists.
Overwrite (y/n)? 

$ ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key
Generating public/private ed25519 key pair.
/etc/ssh/ssh_host_ed25519_key already exists.
Overwrite (y/n)? 
$ ll /etc/ssh/
总用量 604
drwxr-xr-x   2 root root   4096 6月  19 16:18 ./
drwxr-xr-x 136 root root  12288 6月  18 10:42 ../
-rwxrwxrwx   1 root root 553122 8月  12  2021 moduli*
-rwxrwxrwx   1 root root   1580 8月  12  2021 ssh_config*
-rwxrwxrwx   1 root root   3246 6月  19 14:12 sshd_config*
-rw-------   1 root root    668 6月  19 16:18 ssh_host_dsa_key
-rw-r--r--   1 root root    601 6月  19 16:18 ssh_host_dsa_key.pub
-rwxrwxrwx   1 root root    227 6月  16 13:53 ssh_host_ecdsa_key*
-rwxrwxrwx   1 root root    173 6月  16 13:53 ssh_host_ecdsa_key.pub*
-rwxrwxrwx   1 root root    399 6月  16 13:53 ssh_host_ed25519_key*
-rwxrwxrwx   1 root root     93 6月  16 13:53 ssh_host_ed25519_key.pub*
-rwxrwxrwx   1 root root   1679 6月  19 16:21 ssh_host_rsa_key*
-rwxrwxrwx   1 root root    393 6月  19 16:21 ssh_host_rsa_key.pub*
-rwxrwxrwx   1 root root    338 6月  16 13:53 ssh_import_id*

修改权限

$ sudo chmod 600 /etc/ssh/ssh_host_*_key 
$ sudo chmod 644 /etc/ssh/ssh_host_*_key.pub
$ sudo chown root:root /etc/ssh/ssh_host_*_key*

重新生成密钥

sudo rm /etc/ssh/ssh_host_* 
dpkg-reconfigure openssh-server
# 或者
ssh-keygen -A

 查看

$ grep "HostKey" /etc/ssh/sshd_config
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
zghy@ubuntu:~$ systemctl restart ssh
zghy@ubuntu:~$ systemctl status ssh
● ssh.service - OpenBSD Secure Shell server
   Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab
   Active: active (running) since Thu 2025-06-19 16:25:51 CST; 7s ago
  Process: 53434 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
 Main PID: 53435 (sshd)
    Tasks: 1 (limit: 4591)
   CGroup: /system.slice/ssh.service
           └─53435 /usr/sbin/sshd -D

6月 19 16:25:51 ubuntu systemd[1]: Starting OpenBSD Secure Shell server...
6月 19 16:25:51 ubuntu sshd[53435]: Server listening on 0.0.0.0 port 22.
6月 19 16:25:51 ubuntu sshd[53435]: Server listening on :: port 22.
6月 19 16:25:51 ubuntu systemd[1]: Started OpenBSD Secure Shell server.

2. cmd

打开powershell

notepad C:\Users\Administrator\.ssh\known_hosts
# 此时会弹出来txt文件

不用该，关掉就行（就是这个文件有错误）

执行下面的指令自动删除

ssh-keygen -R 192.168.218.128

然后重新连接

ssh 用户名@ubuntu地址ip

输入密码就连接成功了

3.vscode

通过上面两步主机和ubuntu可以ssh了，但是vscode还不可以（数据没更新）

简单方法

在ubuntu 的~目录下删除vscode的服务

$ rm -rf .vscode-server/

然后在vscode的ssh（.ssh\config）中把主机名字与ip都删了，刷新一下，重新添加，再连接就好了