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• Generate Ssh Key Linux Azure
• Linux Generate Ssh Key For Root 1
• Generate Ssh Key Putty

Part 1: SSH key without a password. To set up a passwordless SSH connection for the root user you need to have root access on the server. Easiest method is to temporarily allow root to log in over ssh via password. One way or another you need root access on the server to do this. Aug 19, 2019 Secure Shell (SSH) is an encrypted protocol used by Linux users to connect to their remote servers. Generally, there are two ways for clients to access their servers – using password based authentication or public key based authentication. Using SSH keys for authentication is highly recommended, as a safer alternative to passwords. You can generate an SSH key pair directly in cPanel, or you can generate the keys yourself and just upload the public one in cPanel to use with your hosting account. When generating SSH keys yourself under Linux, you can use the ssh-keygen command. To do so follow these steps: Open up the Terminal; Type in the following command.

With a secure shell (SSH) key pair, you can create a Linux virtual machine on Azure that defaults to using SSH keys for authentication, eliminating the need for passwords to sign in. VMs created with the Azure portal, Azure CLI, Resource Manager templates, or other tools can include your SSH public key as part of the deployment, which sets up SSH key authentication for SSH connections.

1. Red Hat Enterprise Linux 6 uses SSH Protocol 2 and RSA keys by default (see Section 14.1.3, “Protocol Versions” for more information). Do not generate key pairs as root, as only root would be able to use those keys. Before reinstalling your system, back up the /.ssh/ directory to keep the generated key pair.
2. Red Hat Enterprise Linux 6 uses SSH Protocol 2 and RSA keys. Including root. To generate a DSA key pair for version 2 of the SSH protocol, follow.

This article provides detailed background and steps to create and manage an SSH RSA public-private key file pair for SSH client connections. If you want quick commands, see How to create an SSH public-private key pair for Linux VMs in Azure.

For additional ways to generate and use SSH keys on a Windows computer, see How to use SSH keys with Windows on Azure.

Overview of SSH and keys

SSH is an encrypted connection protocol that allows secure sign-ins over unsecured connections. SSH is the default connection protocol for Linux VMs hosted in Azure. Although SSH itself provides an encrypted connection, using passwords with SSH connections still leaves the VM vulnerable to brute-force attacks or guessing of passwords. A more secure and preferred method of connecting to a VM using SSH is by using a public-private key pair, also known as SSH keys.

• The public key is placed on your Linux VM, or any other service that you wish to use with public-key cryptography.

• The private key remains on your local system. Protect this private key. Do not share it.

When you use an SSH client to connect to your Linux VM (which has the public key), the remote VM tests the client to make sure it possesses the private key. If the client has the private key, it's granted access to the VM.

Depending on your organization's security policies, you can reuse a single public-private key pair to access multiple Azure VMs and services. You do not need a separate pair of keys for each VM or service you wish to access.

Your public key can be shared with anyone, but only you (or your local security infrastructure) should possess your private key.

Private key passphrase

The SSH private key should have a very secure passphrase to safeguard it. This passphrase is just to access the private SSH key file and is not the user account password. When you add a passphrase to your SSH key, it encrypts the private key using 128-bit AES, so that the private key is useless without the passphrase to decrypt it. If an attacker stole your private key and that key did not have a passphrase, they would be able to use that private key to sign in to any servers that have the corresponding public key. If a private key is protected by a passphrase, it cannot be used by that attacker, providing an additional layer of security for your infrastructure on Azure.

Supported SSH key formats

Azure currently supports SSH protocol 2 (SSH-2) RSA public-private key pairs with a minimum length of 2048 bits. Other key formats such as ED25519 and ECDSA are not supported.

SSH keys use and benefits

When you create an Azure VM by specifying the public key, Azure copies the public key (in the .pub format) to the ~/.ssh/authorized_keys folder on the VM. SSH keys in ~/.ssh/authorized_keys are used to challenge the client to match the corresponding private key on an SSH connection. In an Azure Linux VM that uses SSH keys for authentication, Azure configures the SSHD server to not allow password sign-in, only SSH keys. Therefore, by creating an Azure Linux VM with SSH keys, you can help secure the VM deployment and save yourself the typical post-deployment configuration step of disabling passwords in the sshd_config file.

If you do not wish to use SSH keys, you can set up your Linux VM to use password authentication. If your VM is not exposed to the Internet, using passwords may be sufficient. However, you still need to manage your passwords for each Linux VM and maintain healthy password policies and practices, such as minimum password length and regular updates. Using SSH keys reduces the complexity of managing individual credentials across multiple VMs.

Generate keys with ssh-keygen

To create the keys, a preferred command is ssh-keygen, which is available with OpenSSH utilities in the Azure Cloud Shell, a macOS or Linux host, the Windows Subsystem for Linux, and other tools. ssh-keygen asks a series of questions and then writes a private key and a matching public key.

SSH keys are by default kept in the ~/.ssh directory. If you do not have a ~/.ssh directory, the ssh-keygen command creates it for you with the correct permissions.

Basic example

The following ssh-keygen command generates 2048-bit SSH RSA public and private key files by default in the ~/.ssh directory. If an SSH key pair exists in the current location, those files are overwritten.

Detailed example

The following example shows additional command options to create an SSH RSA key pair. If an SSH key pair exists in the current location, those files are overwritten.

Command explained

ssh-keygen = the program used to create the keys

-m PEM = format the key as PEM

-t rsa = type of key to create, in this case in the RSA format

-b 4096 = the number of bits in the key, in this case 4096

-C 'azureuser@myserver' = a comment appended to the end of the public key file to easily identify it. Normally an email address is used as the comment, but use whatever works best for your infrastructure.

-f ~/.ssh/mykeys/myprivatekey = the filename of the private key file, if you choose not to use the default name. A corresponding public key file appended with .pub is generated in the same directory. The directory must exist.

-N mypassphrase = an additional passphrase used to access the private key file.

Example of ssh-keygen

Saved key files

Enter file in which to save the key (/home/azureuser/.ssh/id_rsa): ~/.ssh/id_rsa

The key pair name for this article. Having a key pair named id_rsa is the default; some tools might expect the id_rsa private key file name, so having one is a good idea. The directory ~/.ssh/ is the default location for SSH key pairs and the SSH config file. If not specified with a full path, ssh-keygen creates the keys in the current working directory, not the default ~/.ssh.

List of the ~/.ssh directory

Key passphrase

Enter passphrase (empty for no passphrase):

It is strongly recommended to add a passphrase to your private key. Without a passphrase to protect the key file, anyone with the file can use it to sign in to any server that has the corresponding public key. Adding a passphrase offers more protection in case someone is able to gain access to your private key file, giving you time to change the keys.

Generate keys automatically during deployment

If you use the Azure CLI to create your VM, you can optionally generate SSH public and private key files by running the az vm create command with the --generate-ssh-keys option. The keys are stored in the ~/.ssh directory. Note that this command option does not overwrite keys if they already exist in that location.

Provide SSH public key when deploying a VM

To create a Linux VM that uses SSH keys for authentication, provide your SSH public key when creating the VM using the Azure portal, CLI, Resource Manager templates, or other methods. When using the portal, you enter the public key itself. If you use the Azure CLI to create your VM with an existing public key, specify the value or location of this public key by running the az vm create command with the --ssh-key-value option.

If you're not familiar with the format of an SSH public key, you can see your public key by running cat as follows, replacing ~/.ssh/id_rsa.pub with your own public key file location:

Output is similar to the following (here redacted):

If you copy and paste the contents of the public key file into the Azure portal or a Resource Manager template, make sure you don't copy any additional whitespace or introduce additional line breaks. For example, if you use macOS, you can pipe the public key file (by default, ~/.ssh/id_rsa.pub) to pbcopy to copy the contents (there are other Linux programs that do the same thing, such as xclip).

If you prefer to use a public key that is in a multiline format, you can generate an RFC4716 formatted key in a pem container from the public key you previously created.

To create a RFC4716 formatted key from an existing SSH public key:

SSH to your VM with an SSH client

With the public key deployed on your Azure VM, and the private key on your local system, SSH to your VM using the IP address or DNS name of your VM. Replace azureuser and myvm.westus.cloudapp.azure.com in the following command with the administrator user name and the fully qualified domain name (or IP address):

If you provided a passphrase when you created your key pair, enter the passphrase when prompted during the sign-in process. (The server is added to your ~/.ssh/known_hosts folder, and you won't be asked to connect again until the public key on your Azure VM changes or the server name is removed from ~/.ssh/known_hosts.)

If the VM is using the just-in-time access policy, you need to request access before you can connect to the VM. For more information about the just-in-time policy, see Manage virtual machine access using the just in time policy.

Use ssh-agent to store your private key passphrase

To avoid typing your private key file passphrase with every SSH sign-in, you can use ssh-agent to cache your private key file passphrase. If you are using a Mac, the macOS Keychain securely stores the private key passphrase when you invoke ssh-agent.

Verify and use ssh-agent and ssh-add to inform the SSH system about the key files so that you do not need to use the passphrase interactively.

Now add the private key to ssh-agent using the command ssh-add.

Generate Ssh Key Linux Azure

The private key passphrase is now stored in ssh-agent.

Use ssh-copy-id to copy the key to an existing VM

If you have already created a VM, you can install the new SSH public key to your Linux VM with a command similar to the following:

Create and configure an SSH config file

You can create and configure an SSH config file (~/.ssh/config) to speed up log-ins and to optimize your SSH client behavior.

The following example shows a simple configuration that you can use to quickly sign in as a user to a specific VM using the default SSH private key.

Create the file

Edit the file to add the new SSH configuration

Example configuration

Add configuration settings appropriate for your host VM.

You can add configurations for additional hosts to enable each to use its own dedicated key pair. See SSH config file for more advanced configuration options.

Now that you have an SSH key pair and a configured SSH config file, you are able to sign in to your Linux VM quickly and securely. When you run the following command, SSH locates and loads any settings from the Host myvm block in the SSH config file.

The first time you sign in to a server using an SSH key, the command prompts you for the passphrase for that key file.

Next steps

Next up is to create Azure Linux VMs using the new SSH public key. Generate private public key pair linux 2048 rsa. Azure VMs that are created with an SSH public key as the sign-in are better secured than VMs created with the default sign-in method, passwords.

Connect to a server by using SSH on Linux or Mac OS X

This article provides steps for connecting to a cloud server froma computer running Linux® or MacOS® X by using Secure Shell (SSH).It also discusses generating an SSH key and adding a public key tothe server.

Introduction

SSH is a protocol through which you can access your cloud server and runshell commands. You can use SSH keys to identify trusted computers withoutthe need for passwords and to interact with your servers.

SSH is encrypted with Secure Sockets Layer (SSL), which makes it difficultfor these communications to be intercepted and read.

Note: Many of the commands in this article must be run on your localcomputer. The default commands listed are for the Linux command line orMacOS X Terminal. To make SSH connections from Windows®, you can use a clientsimilar to the free program, PuTTY.To generate keys, you can use a related program, PuTTYGen.

Log in

Using the Internet Protocol (IP) address and password for your cloud server, log in byrunning the following ssh command with username@ipaddress as the argument:

Linux Generate Ssh Key For Root 1

The system prompts you to enter the password for the account to which you’reconnecting.

Remote host identification

If you rebuilt your cloud server, you might get the following message:

One of the security features of SSH is that when you log in to a cloudserver, the remote host has its own key that identifies it. When you tryto connect, your SSH client checks the server’s key against any keysthat it has saved from previous connections to that IP address. After yourebuild a cloud server, that remote host key changes, so your computerwarns you of possibly suspicious activity.

To ensure the security of your server, you canuse the web console in the Cloud Control Panel to verify your server’s new key.If you’re confident that you aren’t being spoofed, you can skip thatstep and delete the record of the old SSH host key as follows:

On your local computer, edit the SSH known_hosts file and remove anylines that start with your cloud server’s IP address.

Note: Use the editor of your choice, such as nano on Debian or theUbuntu operating systemor vi on RPM or CENTOS servers. For simplicity, this article just uses nano. If you prefer to use vi,substitute vi for nano in the edit commands.For more on using nano, seehttps://support.rackspace.com/how-to/modify-your-hosts-file/.

If you are not using Linux or MacOS X on your local computer, thelocation of the known_hosts file might differ. Refer to your OS forinformation about the file location. PuTTY on Windows gives you theoption to replace the saved host key.

Generate a new SSH key pair

You can secure SSH access to your cloud server against brute forcepassword attacks by using a public-private key pair. A public key is placed onthe server and a matching private key is placed on your local computer. If youconfigure SSH on your server to accept only connections using keys,then no one can log in by using just a password. Connecting clientsare required to use a private key that has a public key registered onthe server. For more on security, reviewLinux server security best practices.

Use the following steps to generate an SSH key pair:

1. Run the following command using your email address as a label.Substitute your email address for your_email@example.com inthe command.

   A message indicates that your public-private RSA key pair isbeing generated.

   At the prompt, press Enter to use the default location or entera file in which to save the key and press Enter.

2. If you want the additional security of a password for the key pair,enter a passphraseand press Enter. If you don’t want to use a passwordwith the key pair, press Enter to continue without setting one.

   Your key pair is generated, and the output looks similar to the following example:

3. Optionally, add your new key to the local ssh-agent file to enableSSH to find your key without the need to specify its location everytime that you connect:

   You can use an SSH configuration shortcut instead of the ssh-agent fileby following the instructions in the Shortcut configuration sectionlater in this article.

Add the public key to your cloud account

To make it easy to add your key to new cloud servers that you create,upload the public key to your cloud account by following these steps:

1. Log in to the Cloud Control Panel.
2. In the top navigation bar, click Select a Product > Rackspace Cloud.
3. Select Servers > SSH Keys.
4. Click Add Public Key.
5. Enter a key name, such as Work Laptop, to remind you which computer this key is for.
6. Select the region for which you want to store the public key. Tostore your key in multiple regions, repeat these steps foreach region. The key must reside in the same region as the server.

7. Paste the contents of the id_rsa.pub file that you created intothe Public Key field. You can get the file contents by eitheropening the file in a text editor or by running the followingcommand:

8. Click Add Public Key.

If you want to add the key manually, instead of by using the Control Panel, reviewLinux server security best practicesand use the following command:

Create a new server by using a stored key

When you create a new cloud server, you can add a stored key to the newserver.

1. On the Create Server page, expand the Advanced Options section.

2. From the SSH Key menu, select your key from the list.

3. If you don’t see a stored key in the list, you can perform one of the following actions:

   • Switch the region for the new server to the region where you have stored the SSH key.
   • Repeat the steps in the preceding section, Add the public key to your cloud account,to add the key to the region in which you want to create the new server.

Add the key to an existing server

You can’t use the Cloud Control Panel to add a public key to anexisting server. Follow these steps to add the key manually:

1. On your cloud server, create a directory named .ssh in the homefolder of the user that you connect to by using SSH.

2. Create or edit the authorized_keys file and add your public key tothe list of authorized keys by using the following command:

   A key is all on one line, so ensure that the key isn’t broken byline breaks. You can have multiple keys in the authorized_keysfile, with one key per line.

3. Set the correct permissions on the key by using the following commands:

4. If you have any issues and need to fix permissions issues, run the following comand:

After you have added the public key to the authorized_keys, you can make an SSHconnection by using your key pair instead of the account password.

Shortcut configuration

Use the following instructions to set up a connection shortcut by creating a~/.ssh/config file on your local computer and adding your server and keydetails to it.

1. Using a text editor, add the following text to the ~/.ssh/config file, changing thevalues to match your server information:

   Each of the following entries describes a feature of the server:

   • Host: A shortcut name that you use to tell SSH to use thisconnection.
   • HostName: The address of the server to which you connect.
   • User: The name of the user account to connect to on theserver.
   • IdentityFile: The location of the private key file (id_rsa).

2. After you set up the config file, connect to the server by usingthe following command with your shortcut name:

Troubleshooting

If you have trouble making a new connection after you restart theserver, use the following steps to help you resolve the issue:

• The best way to troubleshoot SSH or SFTP login issues is to attempt tologin through SSH while logged into the Emergency Console and to watch the log,which typically includes the reason for a failure. If no reason is given,it could be a firewall issue. For RPM servers, run the following command to watch the log:

  For Debian servers, run the following command to watch the log:

• If you get a connection timeout error, check the IP address thatyou used to ensure that it’s correct. You might also check theserver’s iptables to ensure that it isn’t blocking the port used by SSH.
• If you get a connection refused error, you might be trying to useSSH with the wrong port. If you changed your server to listen to aport other than 22, use the -p option with SSH to specifythe port.
• If your login is rejected, then you might have an issuewith your key. Change the sshd configuration to allow passwordconnections by setting PasswordAuthentication to yes. Restartthe server and try again. If you connect after these changes, thenthe issue is with the key and you must verify that the key is in theright place on the server.

• If all else fails, review your changes and restart the SSH daemon onthe server by running the following command:

  If you get a message that the SSH service is unknown, run thecommand with sshd as the service name instead.

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