Start SSH Server Ubuntu: A Comprehensive Guide


Welcome to our informative guide on starting an SSH server on Ubuntu! Are you ready to delve into the world of secure remote access to your Ubuntu machine? If so, you’ve come to the right place. In this article, we will provide a step-by-step explanation of how to set up an SSH server on your Ubuntu system, enabling you to connect to it securely from anywhere in the world. So, let’s get started and unlock the power of SSH!

What is SSH?

Before we dive into the process of starting an SSH server on Ubuntu, let’s first understand what SSH is. SSH, or Secure Shell, is a cryptographic network protocol that allows secure and encrypted communication between two computers. It provides a secure channel over an unsecured network, enabling users to access and control remote machines securely. Whether you are a system administrator, a developer, or an enthusiast looking to manage your Ubuntu machine remotely, SSH is an indispensable tool in your arsenal.

Setting Up an SSH Server on Ubuntu

Now that we have a good understanding of what SSH is, let’s proceed with the process of setting up an SSH server on your Ubuntu system. By following these step-by-step instructions, you’ll have your SSH server up and running in no time:

Step 1: Update and Upgrade

Before we begin, it’s essential to ensure that your Ubuntu system is up to date. Open a terminal and execute the following commands:

$ sudo apt update$ sudo apt upgrade

Step 2: Install OpenSSH Server

Next, we need to install the OpenSSH server package on our Ubuntu machine. Execute the following command:

$ sudo apt install openssh-server

Step 3: Configure SSH Server

Once the installation is complete, we need to configure the SSH server. The configuration file for the SSH server is located at /etc/ssh/sshd_config. Open the file using a text editor:

$ sudo nano /etc/ssh/sshd_config

Step 4: Customize SSH Server Configuration

Within the SSH server configuration file, you can customize various parameters to suit your needs. Here are a few key options:

Option Description
Port The port number on which the SSH server listens for incoming connections.
PermitRootLogin Specifies whether root can log in using SSH.
PasswordAuthentication Specifies whether password-based authentication is allowed.

Step 5: Start SSH Server

After customizing the SSH server configuration, save the file and exit the text editor. To apply the changes, restart the SSH server:

$ sudo systemctl restart ssh

Step 6: Configure Firewall

To ensure that the SSH server is accessible from remote machines, you need to configure your firewall to allow incoming SSH connections:

$ sudo ufw allow ssh

Step 7: Connect to Your Ubuntu SSH Server

With the SSH server up and running, you can now connect to it remotely using an SSH client. On your client machine, open a terminal and execute the following command:

$ ssh [username]@[server_ip_address]

Advantages of Using SSH Server on Ubuntu

Now that you have successfully set up an SSH server on your Ubuntu system, let’s explore some of the advantages it offers:

1. Secure Remote Access

With SSH, you can securely access and control your Ubuntu machine from anywhere in the world, as long as you have an internet connection. The communication between your client and server is encrypted, ensuring the confidentiality of your data.

2. Flexible File Transfer

Using SSH, you can easily transfer files between your local machine and the remote Ubuntu server. The secure file transfer protocol (SFTP) built into SSH allows for seamless and encrypted file transfers.

3. Remote Command Execution

SSH enables you to execute commands on your Ubuntu server remotely. This functionality is particularly useful for system administrators who need to manage multiple servers without physically accessing them.

4. Tunneling and Port Forwarding

SSH supports tunneling and port forwarding, allowing you to securely access services running on your remote Ubuntu server. This means you can access web servers, databases, and other services as if they were running on your local machine.

5. Public Key Authentication

SSH supports public key authentication, eliminating the need to enter a password every time you connect to your Ubuntu server. This not only improves security but also makes the authentication process more convenient.

6. Robust Security Measures

SSH incorporates various security measures, including encryption algorithms, host key verification, and protection against brute-force attacks. By utilizing SSH, you enhance the overall security of your Ubuntu system.

7. Wide Range of Client Support

SSH is a widely adopted protocol and is supported by various SSH clients available for different operating systems. Whether you are using Windows, macOS, or Linux, you can find an SSH client that suits your needs.

SSH Server Configuration Table

Configuration Option Description Default Value
Port The port number on which the SSH server listens for incoming connections. 22
PermitRootLogin Specifies whether root can log in using SSH. prohibit-password
PasswordAuthentication Specifies whether password-based authentication is allowed. yes

Frequently Asked Questions (FAQs)

1. Can I change the default SSH port?

Yes, you can modify the default SSH port by editing the SSH server configuration file (/etc/ssh/sshd_config) and changing the value of the Port option. Don’t forget to update your firewall rules accordingly.

2. How can I disable password-based authentication?

To disable password-based authentication, set the PasswordAuthentication option to “no” in the SSH server configuration file. However, ensure that you have set up an alternative authentication method, such as public key authentication, before disabling password authentication.

3. What are the security implications of enabling root login via SSH?

Enabling root login via SSH poses security risks as it allows direct access to the root account. It is generally recommended to disable root login and use a non-root account with sudo privileges instead.

4. Can I restrict SSH access to specific users?

Yes, you can restrict SSH access to specific users by modifying the AllowUsers or AllowGroups option in the SSH server configuration file. Only the specified users or groups will be allowed to connect via SSH.

5. How can I generate SSH key pairs?

To generate SSH key pairs, you can use the ssh-keygen command on your local machine. This will create a public-private key pair that can be used for secure authentication with SSH servers.

6. Can I use SSH to access my Ubuntu server from Windows?

Yes, you can use SSH to access your Ubuntu server from Windows by using SSH clients such as PuTTY or Windows PowerShell. These clients provide a Windows-friendly interface to connect to SSH servers.

7. How do I enable X11 forwarding with SSH?

To enable X11 forwarding with SSH, you need to include the -X or -Y option when connecting to the SSH server. This allows you to run graphical applications on the remote server and display them on your local machine.


Congratulations on successfully starting an SSH server on your Ubuntu machine! You are now equipped with the knowledge and tools to securely access and manage your system remotely. SSH provides a powerful and secure means of interacting with your Ubuntu server, offering flexibility, robust security, and convenient remote administration capabilities. So why wait? Start harnessing the power of SSH and unlock a world of possibilities for your Ubuntu system.


We hope this guide has been helpful in guiding you through the process of starting an SSH server on Ubuntu. Remember, SSH grants you secure remote access, flexible file transfer, and the ability to execute commands and tunnel services conveniently. Always prioritize security by modifying default settings, using public key authentication, and keeping your system up to date. Enjoy the secure remote management capabilities SSH brings to your Ubuntu system!


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