1. Check the current SSH version installed on the system
Use the command ssh -Vto view the current ssh version, the output is as follows:
OpenSSH_7.6p1 Ubuntu-4ubuntu0.7, OpenSSL 1.0.2n 7 Dec 2017
2. To install dependencies, execute the following commands in sequence
sudo apt update
sudo apt install build-essential zlib1g-dev libssl-dev
3. Set up the environment
In order to create a suitable environment to install the OpenSSH service, an installation environment needs to be created
sudo mkdir /var/lib/sshd
sudo chmod -R 700 /var/lib/sshd/
sudo chown -R root:sys /var/lib/sshd/
4. Download the source code and install it
Download OpenSSH version 9.3 from any available HTTP mirror , or wgetdirectly in the terminal using the command
Download the source code to any folder:
wget -c https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-9.3p1.tar.gz
Unzip:
tar -xzf openssh-9.3p1.tar.gz
Enter the source code folder path:
cd openssh-9.3p1/
PAMIf you want to enable and support when installing , you need to add and options SELinuxrespectively , and you need to install all the necessary header files for them to work properly.--with-pam--with-selinux
Installation dependencies:
sudo apt install libpam0g-dev libselinux1-dev libkrb5-dev
To install ssh, execute the following three commands in sequence:
./configure --with-kerberos5 --with-md5-passwords --with-pam --with-selinux --with-privsep-path=/var/lib/sshd/ --sysconfdir=/etc/ssh
make
sudo make install
After the installation is complete, restart the system, otherwise the remote connection will continue to use the old version
5. Check for new versions
view locally
Open a new terminal and run:
ssh -V
remote viewing
Check if the OpenSSH version has changed on the remote machine:
ssh -v user@ip
Find the line in the output information Remote protocol version. If the old version number is displayed,
you need to copy the new version. The operation is as follows:
cd /usr/sbin
mv sshd sshd.bak # 备份旧版本的sshd
sudo cp /usr/local/sbin/sshd sshd # 复制新版本sshd
Use the remote view version command again (to be on the safe side, it is recommended to restart after copying):
ssh -v [email protected]
The version has been updated to 9.3
The various OpenSSH configuration files are located at:
~/.ssh/*– This directory stores user-specific ssh client configurations (ssh aliases) and keys./etc/ssh/ssh_config– This file contains the system-wide ssh client configuration./etc/ssh/sshd_config– Contains sshd service configuration.
6. Remote connection
ssh <user>@<ip>
