SSH or known by its full name Secure Shell Protocol, is a cryptographic network communication protocol that enables two computers to communicate securely over an unsecured network. SSH is highly used for remote login applications and command-line executables such as terminal applications.
For users wishing to connect to servers or other computers with SSH, the client and the remote connection need to both have SSH installed and enabled for this to be possible.
In the following tutorial, you will learn how to install and enable SSH on Rocky Linux 35 Workstation or Server and connect to a remote PC.
Table of Contents
Update Rocky Linux System
Update your Rocky Linux operating system to ensure all existing packages are up to date.
sudo dnf upgrade --refresh -y
Install/Enable SSH/SSHD (OpenSSH)
Depending on what installation you have installed for Rocky Linux users, most often SSH/SSHD, which is named “OpenSSH” on your system, may already be installed.
This can be checked using the following command.
rpm -qa | grep openssh-server
As above, for the system the tutorial is being conducted on SSH is already installed, for users that do not have the package and need to install it, run the following terminal command.
sudo dnf install openssh-server
Type Y, then press the ENTER KEY to proceed.
Once installed, by default, this should be enabled, but for users that have SSH present already on their system, you will need to run the enable command as, by default, for security purposes, it is disabled on fresh installations.
sudo systemctl enable sshd --now
Next, verify the status of SSH using the following command.
systemctl status sshd
Another handy trick is to use the following command to see open connections.
ss -lt | grep ssh
Connect to SSH/SSHD Server
With SSH now installed and enabled, you can connect to a remote system, another remote PC, or a server. Remember, the SSH software must be enabled on both ends for this to work.
First, you will need to have the internal/external IP address or the hostname and preferably the username of the account connecting too, then use the ssh command to begin the connection.
When you connect to the remote SSH instance for the first time, you will receive the following message.
Type YES, then you will be prompted to enter your password; once done, press the ENTER KEY.
Once successfully connected instead of joshua@rockylinux-8, we now see joshua@fedora-36 since your terminal window is logged in to the remote session.
Example output (Connected to Fedora 36 Remote PC):
Disable SSH/SSHD (OpenSSH)
For instances where you do not need SSH running, you should always have this disabled for security purposes. Many malicious bots scan the internet for SSH instances and brute force them if they are not secure.
To disable SSH, use the following command.
sudo systemctl disable sshd --now
When you need to have SSH re-enabled, use the following command.
sudo systemctl enable sshd --now
Comments and Conclusion
In the tutorial, you have learned how to install and enable SSH (OpenSSH) on Rocky Linux 8.
Overall, SSH is the go-to protocol compared to using other similar services such as TELNET which is not secure. However, ensure your firewalls are activated when using SSH over an open-unsecured network.