今天在使用 XShell 连接到新安装的 CentOS Stream9 时，抛出了如下错误：
（1）进入到 /etc/ssh/ 目录，命令如下：
[root@localhost ~]# cd /etc/ssh/ [root@localhost ssh]# ll total 600 -rw-r--r--. 1 root root 578094 Feb 22 20:32 moduli -rw-r--r--. 1 root root 1921 Feb 22 20:32 ssh_config drwxr-xr-x. 2 root root 28 Apr 2 22:28 ssh_config.d -rw-------. 1 root root 3689 Apr 2 22:31 sshd_config drwx------. 2 root root 28 Apr 2 21:11 sshd_config.d -rw-r-----. 1 root ssh_keys 492 Apr 2 21:30 ssh_host_ecdsa_key -rw-r--r--. 1 root root 162 Apr 2 21:30 ssh_host_ecdsa_key.pub -rw-r-----. 1 root ssh_keys 387 Apr 2 21:30 ssh_host_ed25519_key -rw-r--r--. 1 root root 82 Apr 2 21:30 ssh_host_ed25519_key.pub -rw-r-----. 1 root ssh_keys 2578 Apr 2 21:30 ssh_host_rsa_key -rw-r--r--. 1 root root 554 Apr 2 21:30 ssh_host_rsa_key.pub
（2）修改 sshd_config 配置文件，如下：
# possible, but leave them commented. Uncommented options override the # default value. # To modify the system-wide sshd configuration, create a *.conf file under # /etc/ssh/sshd_config.d/ which will be automatically included below Include /etc/ssh/sshd_config.d/*.conf # If you want to change the port on a SELinux system, you have to tell # SELinux about this change. # semanage port -a -t ssh_port_t -p tcp #PORTNUMBER # #Port 22 #AddressFamily any #ListenAddress 0.0.0.0 #ListenAddress :: #HostKey /etc/ssh/ssh_host_rsa_key #HostKey /etc/ssh/ssh_host_ecdsa_key #HostKey /etc/ssh/ssh_host_ed25519_key # Ciphers and keying #RekeyLimit default none # Logging #SyslogFacility AUTH #LogLevel INFO # Authentication: #LoginGraceTime 2m #PermitRootLogin prohibit-password PermitRootLogin yes #StrictModes yes #MaxAuthTries 6 #MaxSessions 10
在该配置文件中添加“PermitRootLogin yes”配置选项，yes 表示运行 root 账号进行远程登录，false 则不允许远程登录。
（3）重启系统，再次使用 XShell 就可以正常连接了。
