Compile, install and upgrade the new version of Openssh.

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# lsb_release -d
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Description:  CentOS Linux release 7.9.2009 (Core)
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#uname -r
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3.10.0-327.el7.x86_64
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#ssh -V
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OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017

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# rpm -qa | grep zlib       # Check the system zlib package environment
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zlib-1.2.7-19.el7_9.x86_64
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zlib-1.2.7-19.el7_9.i686
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# yum install zlib-devel -y
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# rpm -qa | grep zlib
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zlib-1.2.7-19.el7_9.x86_64
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zlib-devel-1.2.7-19.el7_9.x86_64
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zlib-1.2.7-19.el7_9.i686

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# tar -xvf openssl-1.1.1l.tar.gz
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# cd openssl-1.1.1l
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# ./config --perfix=/usr/local/openssl
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# make && make install
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# echo '/usr/local/openssl/lib' >> /etc/ld.so.conf
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# ldconfig -v
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Check that the compiled installation and the version of openssl that comes with the system are working properly
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# /usr/local/openssl/bin           # Go to the compile openssl directory
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# ./openssl version
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Openssl 1.1.1l  25 Aug 2021        # Compiled openssl version
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# openssl version
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OpenSSL 1.0.2k-fips  26 Jan 2017   # The system comes with a version

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# rpm -qa | grep openssh
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openssh-server-7.4p1-21.el7.x86_64
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openssh-clients-7.4p1-21.el7.x86_64
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openssh-7.4p1-21.el7.x86_64
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####### Backup the original openssh configuration
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# cp -rf /etc/ssh /etc/ssh_bak
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# rpm -e --nodeps `rpm -qa | grep openssh`      # Perform an uninstall of openssh
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# rpm -qa | grep openssh                        # View openssh
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Verify that the base tool is working properly and that commands are executed without errors
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# curl -V
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# wget -V
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# yum --version

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# tar -xvf openssh-8.7.tar.gz
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# cd openssh-8.7
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# ./configure --prefix=/usr/local/openssh --sysconfdir=/etc/ssh  --with-ssl-dir=/usr/local/openssl
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# make && make install
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##### Copy the executable to the system `bin` directory
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# cp /usr/local/openssh/sbin/sshd /usr/sbin/sshd
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# cp /usr/local/openssh/bin/ssh /usr/bin/ssh
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# cp /usr/local/openssh/bin/ssh-keygen /usr/bin/ssh-keygen
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##### Copy the sshd startup script
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# cp contrib/redhat/sshd.init /etc/init.d/sshd

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Port 22                      # list port
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PermitRootLogin yes          # Allow root login
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PasswordAuthentication yes   # password verification
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Add the following to the end of the document:
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KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1

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# /etc/init.d/sshd start
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Starting sshd:                                             [ok]

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# netstat -tpln | grep ssh
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tcp        0      0 0.0.0.0:22               0.0.0.0:*
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添加sshd开机自启
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# chkconfig --list | grep sshd  # Check that the configured ports are OK after the service starts
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# chkconfig sshd on             # Add boot-up
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# chkconfig --list | grep sshd  # Verify that adding boot-up is normal
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sshd             0:off  1:off  2:on  3:on  4:on  5:on  6:off

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# ssh -V
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OpenSSH_8.7p1, OpenSSL 1.1.1l  25 Aug 2021