1. 安装必要组件：
yum install -y gcc openssl-devel pam-devel rpm-build
2. 下载OpenSSH最新版本：
wget http://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-8.3p1.tar.gz
tar -xvf openssh-8.3p1.tar.gz
3. 到openssh-8.3p1目录下编译并安装最新版OpenSSH:
cd openssh-8.3p1
./configure --prefix=/usr --sysconfdir=/etc/ssh --with-zlib --with-md5-passwords --with-tcp-wrappers
4. 如果没报错则执行安装命令
make && make install
5. 查看OpenSSH版本信息
ssh -V
6. 检查配置 将下面几个开启
vi /etc/ssh/sshd_config
PermitRootLogin yes
PubkeyAuthentication yes
PasswordAuthentication yes
7. 设置权限
chmod 600 /etc/ssh/ssh_host_rsa_key
chmod 600 /etc/ssh/ssh_host_ecdsa_key
chmod 600 /etc/ssh/ssh_host_ed25519_key
8. 关闭 Selinux
setenforce 0 #临时关闭Selinux
如果要永久关闭，修改/etc/selinux/config 文件,
将SELINUX=enforcing改为SELINUX=disabled
9. 重启
service sshd restart
如果出现以下异常
/etc/ssh/sshd_config line 81: Unsupported option GSSAPIAuthentication
/etc/ssh/sshd_config line 83: Unsupported option GSSAPICleanupCredentials
则注释掉相关行数即可。
# 验证操作
ssh -V
# ssh反复重启？
查看日志发现ssh在不停的重启
Aug 23 23:11:11 localhost systemd: sshd.service failed. Aug 23 23:11:53 localhost systemd: sshd.service holdoff time over, scheduling restart. Aug 23 23:11:53 localhost systemd: Stopped OpenSSH server daemon. Aug 23 23:11:53 localhost systemd: Starting OpenSSH server daemon... Aug 23 23:13:23 localhost systemd: sshd.service start operation timed out. Terminating. Aug 23 23:13:24 localhost systemd: Failed to start OpenSSH server daemon. Aug 23 23:13:24 localhost systemd: Unit sshd.service entered failed state. Aug 23 23:13:24 localhost systemd: sshd.service failed. Aug 23 23:14:06 localhost systemd: sshd.service holdoff time over, scheduling restart. Aug 23 23:14:06 localhost systemd: Stopped OpenSSH server daemon. Aug 23 23:14:06 localhost systemd: Starting OpenSSH server daemon... Aug 23 23:15:36 localhost systemd: sshd.service start operation timed out. Terminating. Aug 23 23:15:36 localhost systemd: Failed to start OpenSSH server daemon. Aug 23 23:15:36 localhost systemd: Unit sshd.service entered failed state.
解释: 出现命令挂起的原因就是 sshd在启动完成后，没有给systemd发消息，systemd就一直在那傻等，所以下面我们就修改源码，添加消息；
源码修改：
在源码openssh-8.3p1目录下，找sshd.c这个主函数文件，找到调用server_accept_loop 这个函数的行，注意这个函数的定义也在这个文件，不要找错了！
前加一行代码，效果如下：
/* Signal systemd that we are ready to accept connections */ sd_notify(0, "READY=1"); /* Accept a connection and return in a forked child */ server_accept_loop(&sock_in, &sock_out,&newsock, config_s);
相应的，在源文件开头几行添加引用头文件：
#include <systemd/sd-daemon.h>
编译，安装
由于默认的依赖中，不包含sd_notify 这个函数，所以还需要安装依赖的包
yum install systemd-devel
编译时还需要在makefile中指明，编辑文件：Makefile ，找到变量 LIBS，修改如下：
LIBS=-lcrypto -ldl -lutil -lz -lcrypt -lresolv -lsystemd
下面就可以直接编译，安装
make & make install