How To Set Up SSH Keys on Ubuntu 12.04
SSH (Secure Shell) is a protocol that enables secure remote access to a server. SSH keys are a secure and convenient way to log into a remote server without a password. In this article, we will show you how to set up SSH keys on Ubuntu 12.04, a popular Linux distribution that is still widely used despite being nearly a decade old. By following the steps in this guide, you will be able to use SSH keys to securely and easily access your Ubuntu 12.04 server.
Generating SSH Keys
Before we can set up SSH keys on Ubuntu 12.04, we need to generate a pair of SSH keys on our local machine. SSH keys come in pairs, with one key serving as the private key and the other serving as the public key. The private key is kept on the local machine, while the public key is copied to the remote server. When a user attempts to log into the remote server, the server compares the public key it has on file with the private key provided by the user to authenticate the user and grant access.
To generate SSH keys on a Linux or macOS machine, we can use the ssh-keygen command. Open a terminal and enter the following command:
ssh-keygen -t rsa -b 4096
This command generates a new RSA key pair with a 4096-bit key size. The ssh-keygen command will prompt you for a file to save the key pair in. By default, the private key will be saved in a file named “id_rsa” in the “.ssh” directory of your home directory, and the public key will be saved in a file with the same name but with a “.pub” extension. For example:
It is important to keep your private key secure, as anyone who has access to your private key will be able to log into any server that has your public key on file. Make sure to keep a backup of your private key in a safe place.
Copying the Public Key to the Remote Server
Now that we have generated our SSH keys, we need to copy the public key to the remote server. To do this, we can use the ssh-copy-id command. Open a terminal and enter the following command:
Replace “user” with the username you use to log into the remote server, and replace “server” with the hostname or IP address of the remote server. For example:
ssh-copy-id [email protected]
The ssh-copy-id command will prompt you for your password for the remote server. Enter your password and press Enter. The ssh-copy-id command will then copy your public key to the remote server and configure it for use with the SSH server. You should now be able to log into the remote server without a password using the following command:
Enabling Key-Based Authentication
By default, Ubuntu 12.04’s SSH server is configured to allow both password-based and key-based authentication. However, for maximum security, it is recommended to disable password-based authentication and only allow key-based authentication. To do this, we need to edit the SSH server’s configuration file, which is located at “/etc/ssh/sshd_config”.
Open the file in a text editor with root privileges using the following command:
sudo nano /etc/ssh/sshd_config
Find the following line in the file:
Uncomment the line by removing the “#” symbol and change “yes” to “no”:
Save the file and close the text editor. Then, restart the SSH server to apply the changes:
sudo service ssh restart
After restarting the SSH server, password-based authentication will be disabled and only key-based authentication will be allowed. This will help to prevent unauthorized access to your server and ensure that only users with access to the private key can log in.
Setting up SSH keys on Ubuntu 12.04 is a relatively simple process that provides a secure and convenient way to access your server. By following the steps in this guide, you will be able to generate SSH keys, copy the public key to the remote server, and disable password-based authentication. With SSH keys, you can log into your server without a password, making it easier and more secure to manage your server remotely.
It’s important to remember to keep your private key safe and secure, as anyone who has access to it will be able to log into your server. You can protect your private key by setting a passphrase when generating the key and by storing the key on a secure device, such as a encrypted USB drive or a hardware security key. Additionally, it’s a good idea to regularly rotate your keys,
for example, by generating a new set of keys and updating the authorized_keys file on your server. This helps to reduce the risk of a key becoming compromised and ensures that you have access to a secure set of keys at all times.
In addition to security, using SSH keys can also increase your productivity. With passwordless authentication, you won’t need to enter a password every time you log into your server, saving you time and effort. SSH keys are widely used and supported by many operating systems and services, making them a versatile and convenient solution for remote access and automation tasks.
In conclusion, setting up SSH keys on Ubuntu 12.04 is a must-do for anyone who needs to access their server remotely. With the steps outlined in this article, you can easily generate and use SSH keys to securely log into your server and enjoy the benefits of passwordless authentication.
If you have any questions or issues while setting up SSH keys on your Ubuntu 12.04 server, feel free to reach out to the community for help. With a little bit of effort, you can easily secure and streamline your remote access to your server and improve your overall experience.