ubuntu 20.04 ssh aktivieren

admin3 April 2024Last Update :

Unlocking Secure Shell: A Comprehensive Guide to Enabling SSH on Ubuntu 20.04

ubuntu 20.04 ssh aktivieren

Welcome to the definitive guide on activating Secure Shell (SSH) on Ubuntu 20.04. Whether you’re a system administrator, a developer, or an IT enthusiast, mastering SSH is crucial for managing servers and automating tasks securely over the internet. This article will walk you through the process of enabling SSH on Ubuntu 20.04 with precision and clarity, ensuring that your server is both accessible and secure.

Understanding SSH and Its Importance

Before diving into the technicalities, let’s understand what SSH is and why it’s so important in today’s digital landscape. SSH, or Secure Shell, is a network protocol that provides administrators with a secure way to access a remote computer. It is widely used to control web servers, execute remote commands, and manage files over the network.

Prerequisites for Enabling SSH on Ubuntu 20.04

To get started, ensure you have the following:

  • A machine running Ubuntu 20.04
  • Sudo privileges or access to the root user
  • An active internet connection

Step-by-Step Guide to Installing OpenSSH Server

OpenSSH is the most popular tool for using SSH on Ubuntu systems. Here’s how to install it:

Updating Your System

First, update your package list to ensure you have access to the latest versions:

sudo apt update
sudo apt upgrade

Installing OpenSSH Server

Next, install the OpenSSH server package:

sudo apt install openssh-server

Once installed, the SSH service should start automatically. You can check its status with:

sudo systemctl status ssh

Configuring SSH for Enhanced Security

With SSH installed, it’s time to configure it for security:

Editing the SSH Configuration File

Edit the SSH configuration file using your preferred text editor:

sudo nano /etc/ssh/sshd_config

Consider making the following changes:

  • Changing the default SSH port
  • Disabling root login
  • Allowing only specific users to connect

After making changes, restart the SSH service:

sudo systemctl restart ssh

Connecting to Your Ubuntu Server via SSH

To connect from a remote machine, use the following command:

ssh username@your_server_ip

Replace “username” with your actual username and “your_server_ip” with the server’s IP address.

Enhancing SSH Security with Key-Based Authentication

Password-based authentication is vulnerable to brute-force attacks. Switching to key-based authentication adds an extra layer of security.

Generating SSH Key Pair

On the client machine, generate an SSH key pair:

ssh-keygen -t rsa -b 4096

This creates a private key and a public key.

Copying the Public Key to the Server

Use the ssh-copy-id utility to copy the public key to your Ubuntu server:

ssh-copy-id username@your_server_ip

Now you can log in without a password, using the private key as authentication.

FAQ Section

What if I forget my SSH port after changing it?

If you forget the custom SSH port, you’ll need to access the server directly and check the /etc/ssh/sshd_config file for the ‘Port’ directive.

How do I troubleshoot if I can’t connect via SSH?

Check your firewall settings, ensure the SSH service is running, and verify that your client’s IP isn’t blocked by any server-side restrictions.

Is it safe to disable password authentication completely?

While key-based authentication is more secure, disabling password authentication is only recommended if you’re sure you won’t lose your private key.


Enabling SSH on Ubuntu 20.04 is a straightforward process that significantly enhances your server’s accessibility and security. By following this comprehensive guide, you’ve learned not only how to activate SSH but also how to configure it for optimal security. Remember, while SSH is robust, maintaining good security practices is essential for protecting your server against potential threats.


For further reading and advanced configurations, consider these resources:

By staying informed and vigilant, you can ensure that your Ubuntu 20.04 server remains a bastion of security in the ever-evolving landscape of network administration.

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