SSH or Secure Shell is a network communication protocol used for remote login or controlling other remote computers. SSH is used to create a secure connection between the local computer and the remote server. In short, SSH protocol connects two computers securely over an unsecured network. Ubuntu does come built-in with an SSH server but it can be installed manually through the official repository. This article will cover the detailed procedure to install an SSH server on Ubuntu.
Quick answer
To install SSH server on Ubuntu 24.04, run sudo apt install openssh-server, then check it with sudo systemctl status ssh. If UFW is enabled, allow SSH with sudo ufw allow OpenSSH before connecting from another computer.
How to Install SSH Server on Ubuntu 24.04
SSH server does not come pre-installed on Ubuntu and it is not readily available to be installed. However, Ubuntu includes an SSH server in its official repository and it can be installed using the apt package manager. Check the following steps to install the SSH server on Ubuntu 24.04.
Step 1: Update System Repositories
Before installing the SSH server on Ubuntu, make sure all the local packages are up to date. To do so, press CTRL + Alt + T shortcut key to open the Terminal and run this command:
sudo apt update && sudo apt upgrade
Step 2: Install SSH Server
Once the local repositories are updated, install the SSH server on Ubuntu by running the below command:
sudo apt install openssh-server -y
Step 3: Enable SSH Server
After installing the SSH server, make sure that the SSH server is enabled. If the SSH server is not enabled, run this command to enable it:
sudo systemctl enable sshNote: When the SSH server gets enabled, it will continue to run whenever Ubuntu boots up:
Note: To disable the SSH server on Ubuntu, run this command:
sudo systemctl disable sshDisabling the SSH server will also stop it from starting at boot:
Step 4: Start the SSH Server
After enabling the SSH server, you can start the SSH server by running this command:
sudo systemctl start ssh
Alternatively, you can also enable and start the SSH server immediately with a single command, which is given below:
sudo systemctl enable --now ssh
Step 5: Verify SSH Server Installation
Once the SSH server is started, you can verify its installation and running status by executing the below command:
sudo systemctl status ssh
How to Configure or Enable the Firewall on Ubuntu 24.04
Till now you have installed the SSH server on Ubuntu and made it run successfully. Now is the time to use the SSH server to establish a connection with the remote computer or server. But, before making a connection with the server, make sure that ufw (Uncomplicated firewall) is active and able to pass the traffic to the SSH server. To enable the ufw firewall and pass the traffic to the SSH server, check the following steps.
Step 1: Enable the UFW Firewall on Ubuntu
First, enable the ufw firewall on Ubuntu for the SSH server by running this command:
sudo ufw enable
Step 2: Allow the SSH Server to Pass the Traffic through the Firewall
Once the firewall is enabled, execute the given command to allow the inbound SSH connections so that traffic can pass through it:
sudo ufw allow sshStep 3: Check Firewall Status
After activating the firewall, verify whether it is running and passing the traffic to the SSH server through the execution of the below command:
sudo ufw statusNote: To disable and remove the firewall from Ubuntu by running this command:
sudo ufw delete allow sshHow to Connect to the Remote Server using SSH on Ubuntu 24.04
Upon completing the previously provided steps, you have installed and enabled the SSH server on Ubuntu. Now, you are all set to connect and log in to the remote server using the SSH server protocol. To log in to the remote server, you must have the server IP address or the domain name, and the user created on the server.
Note: The SSH server must be installed on both the remote computer and the computer through which the user is making a connection.
To log in to the remote server using the IP address, run this command:
ssh username@ip-addressTo log in to the remote server using the domain name, run this command:
ssh username@domain-nameSet up SSH key authentication
SSH key authentication is more secure than passwords and eliminates the need to type a password each time you connect. The process generates a key pair: a private key that stays on your local machine, and a public key that you copy to the server.
On your local machine, generate an Ed25519 key pair:
ssh-keygen -t ed25519 -C "[email protected]"Press Enter to accept the default file location (~/.ssh/id_ed25519). Adding a passphrase is optional but adds a second layer of protection if your private key is ever exposed.
Copy the public key to the remote server:
ssh-copy-id username@server-ipThis appends your public key to ~/.ssh/authorized_keys on the server. Test that key-based login works before making any further changes:
ssh username@server-ipOnce key login is confirmed, you can disable password authentication to block brute-force attacks. Open /etc/ssh/sshd_config and set:
PasswordAuthentication noSave the file, then restart SSH for the change to take effect:
sudo service ssh restartHow to Configure SSH Server on Ubuntu 24.04
Besides installing and using the SSH server to connect with the remote server, you can also configure or make changes to it. Configuration is often practiced to secure the SSH server by changing its ports and passwords. The SSH server’s configurations are stored in the sshd_config file which you can edit through the nano editor.
However, it is recommended to create a backup of the sshd_config file before making any changes, so in case you corrupted the original file you always have its copy. To create a backup of the sshd_config file run this command:
sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.initial
Once the backup of the sshd_file is created, run this command to edit the sshd_file with the nano editor to configure it:
sudo nano /etc/ssh/sshd_configIn the sshd_file configuration file, first of all, change the port number to a more secure one. For instance, change the port number to 50782 to make it more secure. To do so, uncomment the Port line by removing the # symbol and specify the port number 50782:
Note: It is recommended to set the port number from the range of 49152 to 65535:
Moving forward, change the password authentication mode to a more secure one. To do so, uncomment the PubkeyAuthentication by removing the # symbol and specifying the value Yes, as shown below:
You can also remove the exception of only allowing the root user to login to the server, by uncommenting the PermitRootLogin section and specifying the value no to it, as shown below:
Additionally, you can also prohibit the users from login to the server with empty passwords. To do so, locate the PermitEmptyPasswords section and uncomment it by removing the # symbol and specify the value No to it, as shown below:
You can set the maximum number of authentication entries to stop the user from coming up with different combinations. Doing so will protect your system from being used by unauthorized users who do not have the password and save your important data from stealing. To set the maximum number of authentication entries, simply uncomment the MaxauthTries by removing the # symbol and providing it the number of maximum tries, for instance, I have set the maximum authentication tries to 6, as shown below:
To save the changes made to the configurations file, press the CTRL + O shortcut and then press the Enter key.
Once you are done with the SSH configuration settings, run this command to restart the SSH service to save the changes made to the configuration file:
sudo service ssh restart
Common SSH commands on Ubuntu 24.04
| Task | Command |
|---|---|
| Connect to a server | ssh username@ip-address |
| Connect on a custom port | ssh -p 50782 username@ip-address |
| Copy a file to the server | scp file.txt username@ip-address:~/ |
| Copy a file from the server | scp username@ip-address:~/file.txt . |
| Run a single command remotely | ssh username@ip-address "ls -la" |
| Check SSH service status | sudo systemctl status ssh |
How to Uninstall SSH Server from Ubuntu 24.04
If you are done with using the SSH server or want to remove it from Ubuntu for any other reason. Check the following steps to uninstall the SSH server from Ubuntu 24.04.
Step 1: Stop the SSH Server
To remove the SSH server, first, stop the SSH server on Ubuntu from running, to do so run the below command:
sudo systemctl stop ssh
Step 2: Disable the SSH Server
Once the SSH server is stopped, then, execute the below command to disable the SSH server on Ubuntu:
sudo systemctl disable sshStep 3: Uninstall SSH Server from Ubuntu
After stopping and disabling the SSH server, you can uninstall the SSH server from Ubuntu by running this command:
sudo apt remove openssh-server -y
Before opening SSH access
SSH makes remote login easy, but it also exposes a login service to the network. Use strong account passwords or SSH keys, keep the server updated, and only allow SSH through the firewall when you actually need remote access.
For a home or lab machine, confirm the Ubuntu computer’s IP address before connecting. For an internet-facing server, review the SSH configuration carefully and avoid enabling password login unless you understand the risk.