zlib下载地址：  http://www.zlib.net/

LibreSSL下载地址： https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/

OpenSSH下载地址：  http://mirror.aarnet.edu.au/pub/OpenBSD/OpenSSH/portable/

rpm -ivh mpfr-2.4.1-6.el6.x86_64.rpm

rpm -ivh gmp-devel-4.3.1-7.el6_2.2.x86_64.rpm

rpm -ivh mpfr-devel-2.4.1-6.el6.x86_64.rpm

tar -xzvf zlib-1.2.11.tar.gz

cd zlib-1.2.11

 ./configure --prefix=/usr/local/zlib-1.2.11

 make && make install

libsntp.a(crypto.o): In function `compute_mac':

/usr/local/ntp-4.2.8p13/sntp/crypto.c:79: undefined reference to `EVP_MD_CTX_new'

/usr/local/ntp-4.2.8p13/sntp/crypto.c:117: undefined reference to `EVP_MD_CTX_free'

collect2: ld returned 1 exit status

make[4]: *** [sntp] 错误 1

make[4]: Leaving directory `/usr/local/ntp-4.2.8p13/sntp'

make[3]: *** [all-recursive] 错误 1

make[3]: Leaving directory `/usr/local/ntp-4.2.8p13/sntp'

make[2]: *** [all] 错误 2

make[2]: Leaving directory `/usr/local/ntp-4.2.8p13/sntp'

make[1]: *** [all-recursive] 错误 1

make[1]: Leaving directory `/usr/local/ntp-4.2.8p13'

make: *** [all] 错误 2

cd libressl-3.0.2

./configure --prefix=/usr/local

make

make install

vim /etc/ld.so.conf.d/local.conf  #新建local.conf文件，添加下面一行

     /usr/local/lib   # 将 /usr/local/lib 目录加入到模块加载目录。

ldconfig -v   #重新加载共享模块：

openssl version #查看版本

安装openssh

#--with-ssl-dir  指定ssl的安装目录

#--with-zlib  指定zlib的安装目录

./configure --prefix=/usr/local/openssh-8.1p1 --sysconfdir=/etc/ssh --with-ssl-dir=/usr/local --with-zlib=/usr/local/zlib-1.2.11 --with-md5-passwords

make

make  install 

cd /etc/init.d/

mv sshd sshd.bak

cd /usr/local/openssh-8.1p1/contrib/redhat/

cp -p sshd.init /etc/init.d/sshd

vi /etc/init.d/sshd

SSHD=/usr/local/openssh-8.1p1/sbin/sshd     #25行   SSHD=/usr/sbin/sshd

/usr/local/openssh-8.1p1/bin/ssh-keygen -A  #41行 /usr/bin/ssh-keygen -A

chkconfig --add sshd

chkconfig sshd on

chkconfig --list sshd

service sshd restart

vim /etc/profile

export PATH=/usr/local/openssh-8.1p1/bin:$PATH

CentOS7(RedHat7)需要再做以下操作。

将systemctl下的原ssh相关文件移走,将不然升级后的openssh不兼容。

mv /usr/lib/systemd/system/ssh*  /opt

vi /etc/ssh/sshd_config   //增加下一行

PermitRootLogin yes

service sshd restart
vi /etc/profile 或者  ~/.bash_profile  设置PATH变量

export PATH=/usr/local/openssh-8.1p1/sbin:/usr/local/openssh-8.1p1/bin:$PATH

source /etc/profile

　验证：

ssh -V

openssl  version