Configure SSH Ubuntu Server 14.04: A Comprehensive Guide

Introduction

Welcome to our comprehensive guide on how to configure SSH Ubuntu Server 14.04. In this article, we will guide you through the process of setting up SSH on your Ubuntu Server 14.04, step-by-step. Secure Shell or SSH is a protocol used to access and manage remote computers securely over an unsecured network. SSH allows for the encryption of data sent between the client and the server, making it an excellent choice for secure remote server administration.

SSH is widely used in the IT industry, and it is an essential tool for system administrators. Once you have configured SSH Ubuntu Server 14.04, you will be able to remotely manage your server from any location in the world. This will save you time and effort, as you will no longer need to be physically present to manage your server.

Without further ado, let us dive into the details of how to configure SSH on Ubuntu Server 14.04.

How to Configure SSH Ubuntu Server 14.04

Before we start configuring SSH on Ubuntu Server 14.04, we need to make sure that the server is up-to-date. Run the following command to update the server:

Command Description
sudo apt-get update Updates the Ubuntu Server 14.04

Once the server is updated, we can proceed with installing SSH on Ubuntu Server 14.04. Run the following command to install SSH:

Command Description
sudo apt-get install ssh Installs SSH on Ubuntu Server 14.04

After SSH is installed on Ubuntu Server 14.04, we need to configure it to ensure that it is secure. Below are the steps to configure SSH Ubuntu Server 14.04:

Step 1: Change the SSH Port

By default, SSH listens on port 22. This port is well-known and is often targeted by attackers. Changing the SSH port will make it harder for attackers to compromise your server. To change the SSH port, follow these steps:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “#Port 22” and uncomment it by removing the # symbol. Change the port number to a value between 1024 and 65535. For example, “Port 2222”.
  3. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  4. Restart the SSH service using the following command:
    5. Command Description
    sudo service ssh restart Restarts the SSH service

Step 2: Disable Root Login

By default, the root user can log in via SSH. This is a security risk as the root user has complete access to the system. It is recommended to disable root login and create a new user with sudo privileges. Follow these steps to disable root login:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “PermitRootLogin yes” and change it to “PermitRootLogin no”.
  3. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  4. Restart the SSH service using the following command:
    5. Command Description
    sudo service ssh restart Restarts the SSH service

Step 3: Use SSH Keys for Authentication

SSH keys provide a more secure way of logging into an SSH server than using a password. SSH keys work based on public-key cryptography, where a pair of keys is generated: one private key and one public key. Follow these steps to use SSH keys for authentication:

  1. Generate an SSH key pair on your local machine using the following command:
    2. Command Description
    ssh-keygen Generates an SSH key pair
  2. Copy the public key to the Ubuntu Server 14.04 using the following command:
    3. Command Description
    ssh-copy-id user@server_ip_address Copies the public key to the Ubuntu Server 14.04
  3. Disable password authentication by updating the SSH configuration file using the following command:
    4. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  4. Find the line that says “#PasswordAuthentication yes” and uncomment it by removing the # symbol. Change it to “PasswordAuthentication no”.
  5. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  6. Restart the SSH service using the following command:
    7. Command Description
    sudo service ssh restart Restarts the SSH service
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Step 4: Configure SSH Encryption

SSH uses encryption to secure the data sent between the client and the server. By default, SSH uses the Advanced Encryption Standard (AES) algorithm with Cipher Block Chaining (CBC) mode. This is a secure encryption method, but it can be slow on older hardware. You can choose to use a faster encryption algorithm if you need to. Follow these steps to configure SSH encryption:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “#Ciphers aes128-ctr,aes192-ctr,aes256-ctr” and uncomment it by removing the # symbol. Change it to “Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com”.
  3. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  4. Restart the SSH service using the following command:
    5. Command Description
    sudo service ssh restart Restarts the SSH service

Step 5: Configure SSH Authentication

SSH supports several authentication methods, including password authentication, public-key authentication, and keyboard-interactive authentication. By default, Ubuntu Server 14.04 allows password authentication. However, we recommend disabling password authentication and using public-key authentication for better security. Follow these steps to configure SSH authentication:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “#PubkeyAuthentication yes” and uncomment it by removing the # symbol. Change it to “PubkeyAuthentication yes”.
  3. Find the line that says “#ChallengeResponseAuthentication yes” and uncomment it by removing the # symbol. Change it to “ChallengeResponseAuthentication no”.
  4. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  5. Restart the SSH service using the following command:
    6. Command Description
    sudo service ssh restart Restarts the SSH service

Step 6: Configure SSH Logging

SSH logs all activity that occurs on the SSH server, including successful and failed login attempts. This information can be used to identify and prevent potential security threats. Follow these steps to configure SSH logging:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “#SyslogFacility AUTH” and uncomment it by removing the # symbol. Change it to “SyslogFacility AUTHPRIV”.
  3. Find the line that says “#LogLevel INFO” and uncomment it by removing the # symbol. Change it to “LogLevel VERBOSE”.
  4. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  5. Restart the SSH service using the following command:
    6. Command Description
    sudo service ssh restart Restarts the SSH service

Advantages and Disadvantages of Configuring SSH Ubuntu Server 14.04

Now that we have covered the steps to configure SSH Ubuntu Server 14.04, let us take a look at the advantages and disadvantages.

Advantages of Configuring SSH Ubuntu Server 14.04

  1. Secure remote server management: SSH provides a secure way to manage your server remotely.
  2. Encryption: All data sent between the client and the server is encrypted, making SSH a secure protocol.
  3. Authentication: SSH supports several authentication methods, including public-key authentication, which is more secure than password authentication.
  4. Logging: SSH logs all activity that occurs on the server, making it easier to identify potential security threats.

Disadvantages of Configuring SSH Ubuntu Server 14.04

  1. Complexity: Configuring SSH on Ubuntu Server 14.04 can be complex and time-consuming, especially for novice users.
  2. Security risks: If SSH is not configured correctly, it can pose security risks to your server.
  3. Resource-intensive: SSH can be resource-intensive, especially if you are using an encryption algorithm that requires a lot of CPU power.

Table of SSH Commands

Command Description
sudo apt-get update Updates the Ubuntu Server 14.04
sudo apt-get install ssh Installs SSH on Ubuntu Server 14.04
sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
sudo service ssh restart Restarts the SSH service
ssh-keygen Generates an SSH key pair
ssh-copy-id user@server_ip_address Copies the public key to the Ubuntu Server 14.04

Frequently Asked Questions

Q1. What is SSH?

A1. SSH or Secure Shell is a protocol used to access and manage remote computers securely over an unsecured network. SSH allows for the encryption of data sent between the client and the server, making it an excellent choice for secure remote server administration.

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Q2. Why do I need to configure SSH Ubuntu Server 14.04?

A2. Configuring SSH on Ubuntu Server 14.04 is essential for secure remote server management. SSH provides a secure way to manage your server remotely and encrypts all data sent between the client and the server.

Q3. How do I change the SSH port on Ubuntu Server 14.04?

A3. To change the SSH port on Ubuntu Server 14.04, follow these steps:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config Opens the SSH configuration file
  2. Find the line that says “#Port 22” and uncomment it by removing the # symbol. Change the port number to a value between 1024 and 65535. For example, “Port 2222”.
  3. Save the changes and exit the editor by pressing “CTRL + X”, then “Y”, and finally “ENTER”.
  4. Restart the SSH service using the following command:
    5. Command Description
    sudo service ssh restart Restarts the SSH service

Q4. How do I disable root login on Ubuntu Server 14.04?

A4. To disable root login on Ubuntu Server 14.04, follow these steps:

  1. Open the SSH configuration file using the following command:
    2. Command Description
    sudo nano /etc/ssh/sshd_config

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