Introduction
Secure Shell (SSH) is a network protocol used to securely access and manage systems remotely. Regularly updating SSH credentials, including both passwords and keys, is a crucial part of maintaining security. In this post, we’ll walk through the steps to change your SSH credentials on a Linux system.
Understanding SSH Authentication
SSH primarily uses two types of authentication: password-based and key-based. Password-based authentication is straightforward, involving a username and a password. Key-based authentication uses a pair of cryptographic keys: a public key that can be shared and a private key that must be kept secure.
Changing SSH Passwords
Step 1: Open a Terminal
Access your terminal.
Step 2: Log in as the User
If you’re not logged in as the user whose password you want to change, switch to that user. Type su - username, replacing “username” with the actual username, and press Enter.
Step 3: Change Password
To change the password, simply type passwd and press Enter. You’ll be prompted to enter the new password twice for confirmation.
Updating SSH Key-Based Authentication
Step 1: Generate a New SSH Key Pair
Open your terminal and enter ssh-keygen. Follow the prompts to generate a new key pair. By default, this creates a .ssh directory in your home directory with the private key (id_rsa) and public key (id_rsa.pub).
Step 2: Deploy the New Public Key
Copy your new public key to the server. You can do this manually by editing the ~/.ssh/authorized_keys file on the server and replacing the old public key with the new one.
Step 3: Verify the Connection
After updating the key on the server, try logging in to ensure the new key works correctly.
Conclusion
Changing your SSH credentials is a simple yet vital part of maintaining your system’s security. Remember, for passwords, use strong, unique passwords, and for SSH keys, keep your private key secure and update your keys regularly.