yum install -y telnet-server.x86_64
yum install -y telnet.x86_64
yum install  -y xinetd.x86_64 
systemctl enable xinetd.service
systemctl enable telnet.socket
systemctl start telnet.socket
systemctl start xinetd
mv /etc/securetty /etc/securetty.bak

#备份与卸载 
mkdir  /etc/ssh_oldbak/
mv  /etc/ssh/*   /etc/ssh_oldbak/
rpm -e `rpm -qa |grep openssh`

#安装依赖
yum install  -y gcc gcc-c++ glibc make autoconf openssl openssl-devel pcre-devel  pam-devel
yum install  -y pam* zlib*

#编译安装
cd openssh-7.9p1/
./configure -prefix=/usr -sysconfdir=/etc/ssh -with-md5-passwords -with-pam -with-ssl-dir=/usr/include/openssl -without-hardening
make && make install

#将原来备份的配置文件拷贝回来
mv /etc/ssh/sshd_config /etc/ssh/sshd_config.bak
cp  /etc/ssh_oldbak/sshd_config  /etc/ssh/sshd_config

#从程序包拷贝可执行文件
cp contrib/redhat/sshd.init /etc/init.d/sshd
chmod +x /etc/init.d/sshd 

#添加到自启动
chkconfig --add sshd
chkconfig sshd on

[Unit]

Description=OpenSSH server daemon

Documentation=man:sshd(8) man:sshd_config(5)

# After=network.target sshd-keygen.service

# Wants=sshd-keygen.service

After=network.target

[Service]

# Type=notify

# EnvironmentFile=/etc/sysconfig/sshd

# ExecStart=/usr/sbin/sshd -D $OPTIONS

ExecStart=/usr/sbin/sshd

# ExecReload=/bin/kill -HUP $MAINPID

# KillMode=process

# Restart=on-failure

# RestartSec=42s

[Install]

WantedBy=multi-user.target

设置如下：
PermitRootLogin  yes
PasswordAuthentication  yes
注销sshd的配置文件（sshd_config）的如下配置:
#GSSAPIAuthentication yes
#GSSAPICleanupCredentials yes
#UsePAM yes

systemctl restart sshd
systemctl enable sshd

openssl version -a

tar zxvf openssl-1.1.1c.tar.gzcd openssl-1.0.1g

cd openssl-1.1.1c

./config --prefix=/usr/local/openssl  #检查环境

./config   -t

make     #编译

make install      #编译安装

cd /usr/local

ldd /usr/local/openssl/bin/openssl    #检查函数库

echo "/usr/local/openssl/lib" >> /etc/ld.so.conf    #添加所缺函数库

ldconfig -v        #更新函数库

openssl/bin/openssl version      #查看新安装的版本

which openssl           #查看旧版本openssl命令在哪里

mv /bin/openssl /usr/bin/openssl.old      #将旧版本openssl移除

ln -s /usr/local/openssl/bin/openssl /usr/bin/openssl           #新版本制作软链接

openssl version         最后查看版本，更新完毕