If you have a server in the cloud, then the only way to connect to it is via an SSH connection. But occasionally, if you mistakenly mistype your password, or simply forget it, then the login process may result in a “Too Many Authentication Failures” error.

If this happens to you then – don’t worry! In this post we will discuss different ways to avoid this problem in the future.

Let’s get started!

What are “Too Many Authentication Failures”?

If you make multiple consecutive login attempts on your server, either using a wrong password or an SSH key, then you are likely to see the following error message:

Received disconnect from host: 2: Too many authentication failures for root

”Too many authentication failures” is an error message commonly encountered in SSH (Secure Shell) services. This is a security measure to prevent unauthorized access and prevent bots from repeatedly spamming your server.

3 Ways to Fix Too Many Authentication Failures

In this section, we will explain how using SSH keys can help in avoiding the “Too many authentication failures” error, but before we start, make sure that you have added the public SSH key on your server.

 If you are using RunCloud, you can configure SSH using our intuitive web interface.

Method 1: Use SSH Key with Command Line

A quick and easy way to avoid authentication failures is by using an SSH key and specifying the path of this SSH identity file directly in the login command to avoid any ambiguity.

By doing so, you bypass the SSH agent and force the use of the specified key, which can help resolve connection issues related to key confusion or agent problems.

Here’s how you can do it:

  1. Restrict the Permissions for SSH key: Before using the identity file, make sure it has the correct permissions set. This can be done with the following command:
chmod 600 /path/to/your/identity_file

This command restricts the file so that only the owner can read and write to it, which is the recommended setting for SSH keys.

  1. Specify Identity File in SSH Command: When connecting to the server, you can specify the identity file using the -i option in the SSH command:
ssh -i /path/to/your/identity_file username@hostname

Replace /path/to/your/identity_file with the actual path to your SSH private key, username with your username, and hostname with the server’s hostname or IP address.

Method 2: Use Unique SSH Key for Each Server (Recommended)

As we have discussed in our SSH service hardening guide, it is recommended to use a different key when connecting to different servers via SSH. Using a unique SSH key for each server can prevent cross-contamination between servers, and reduce the risk of accidentally leaking credentials for all the servers.

If you are using RunCloud, you can easily add a unique SSH key for each user account on your server using the “SSH” tab in your server settings page.

When using a new key for each server, it can be difficult to determine which key belongs to which server. To solve this problem, you can specify the keys in the ~/.ssh/config file on your local machine along with other necessary information.

Here’s how you can manage multiple connections by specifying an identity file and username for each server:

Open the ssh configuration file (located at ~/.ssh/config) on your local machine in a text editor. You can use any text editor such as notepad, VS code, or even a CLI-based editor such as nano. In that file, paste the following example:

# Server 1
Host server1
    HostName server1.example.com
    User myuser1
    IdentityFile ~/.ssh/id_rsa_server1

# Server 2
Host server2
    HostName server2.example.com
    User myuser2
    IdentityFile ~/.ssh/id_rsa_server2

In the configuration above, Host is an alias for the server, HostName is the actual hostname or IP address, User is the username for the SSH connection, and IdentityFile is the path to the private key file used for authentication.

Edit the example configuration and replace the dummy values with the actual values – the values for hostname, user, and identifyFile will be their respective values, but you can set the Host variable to anything descriptive.

In the above example, we have added a server in our configuration file and named it server1. To connect to this server we can simply specify its name in the SSH command, and your computer will automatically use the correct credentials for logging in. 

ssh server1

In the above example, server1 is the name of the server that we specified in the configuration file.

This is the recommended way to do this, because by using the config file you streamline the process of connecting to various servers, making it more efficient and less prone to mistakes. System administrators and developers who frequently access multiple servers prefer this technique for the following reasons:

  1. Simplified Connection Commands: Instead of typing long SSH commands with usernames and key paths, you can connect to a server with a simple ssh server1 command.
  2. Organized Credentials: Each server has its own entry, making it easy to manage different usernames and keys for each connection.
  3. Enhanced Security: By using unique keys for each server, you reduce the risk of a compromised key affecting multiple servers.
  4. Automated Connection Parameters: The SSH client automatically uses the correct username and key when connecting, reducing the chance of errors.
  5. Ease of Maintenance: Updating a server’s credentials or connection details is as simple as editing the corresponding entry in the config file.

Suggested read: Why Authentication Using SSH Public Key is Better than Using Password and How Do They Work? 

Method 3: Increase MaxAuthTries in SSH

Although you shouldn’t need to, you can optionally choose to change the number of allowed failed attempts by modifying the MaxAuthTries variable in the server configuration.

Here are the step-by-step instructions to increase the MaxAuthTries value in the SSH daemon configuration:

  1. First, you need to connect to the server with the necessary privileges.
  2. On the server, open the SSH daemon configuration file located at /etc/ssh/sshd_config with a text editor of your choice. You will need superuser privileges to edit this file. For example, you can use nano:
sudo nano /etc/ssh/sshd_config
  1. Next, you need to locate the MaxAuthTries directive. If it’s commented out (preceded by a #), you will need to uncomment it by removing the #.
  2. Change the value of MaxAuthTries to a number that suits your needs. The default is usually 6. Increasing it allows more authentication attempts before disconnecting.
MaxAuthTries 10
  1. Save the Configuration File. After making the changes, save the file and exit the text editor. In nano, you can do this by pressing CTRL + X, then Y to confirm, and Enter to save.
  2. Restart the SSH Service Apply the changes by restarting the SSH service. The command to restart the service may vary depending on your system’s init system. Here are two common methods:
#Using systemctl command
sudo systemctl restart sshd
#Using service command
sudo service sshd restart

By following these steps, you will have successfully increased the MaxAuthTries value, allowing more authentication attempts and potentially resolving issues with multiple keys in your SSH agent. Remember to use this setting judiciously, as allowing too many authentication attempts can be a security risk.

Although this method works well for most people, if you want additional security and flexibility, we recommend configuring Fail2ban to automatically block IP addresses which repeatedly login using incorrect credentials.

Wrapping Up

Navigating the complexities of server management and SSH authentication can be daunting. By implementing the methods outlined in this article, you can effectively resolve the “Too many authentication failures for user root” error, and streamline your server management process.

After setting up the SSH authentication, you can start using your server and perform simple actions such as editing files via nano or transferring files via SFTP. Or if you are feeling adventurous, you can perform some advanced tasks such as finding large directories and files in Linux, Copying Files in Linux, or master the echo command.

A secure and efficient server setup is crucial for smoothly managing web applications, but you don’t need to be a Linux expert anymore to deploy websites on the internet.

With RunCloud, you can effortlessly control your server environment, allowing you to focus on building your application without the backend worries. And if you ever encounter any server issues, our professional technical team is always ready to assist you.

Join RunCloud today and experience the peace of mind that comes with one-click web application installations.