SSH keys for user authentication are usually stored in the user's.ssh directory under the home directory. However, in enterprise environments, the location is often different. The default key file name depends on the algorithm, in this case idrsa when using the default RSA algorithm. It could also be, for example, iddsa or idecdsa. For example, entering ssh -i /.ssh/idrsa-remote-ssh yourname@remotehost.yourcompany.com in the input box would generate this entry: Host remotehost.yourcompany.com User yourname HostName another-host-fqdn-or-ip-goes-here IdentityFile /.ssh/idrsa-remote-ssh See Tips and Tricks for details on generating the key shown here.
See full list on cects.com. Jan 03, 2020 Note: SSH keys are always generated as a pair of public (idrsa.pub) and private (idrsa) keys. It's extremely important that you never reveal your private key, and only use your public key for things like GitHub authentication. You can read more about how SSH / RSA key pairs work here. Add your SSH key to ssh-agent. The 'ssh-rsa' key format has the following specific encoding: string 'ssh-rsa' mpint e mpint n Here the 'e' and 'n' parameters form the signature key blob. Signing and verifying using this key format is performed according to the RSASSA-PKCS1-v15 scheme in using the SHA-1 hash. The resulting signature is encoded as follows: string 'ssh-rsa.
-->This article is for Windows users who want to create and use secure shell (SSH) keys to connect to Linux virtual machines (VMs) in Azure. You can also generate and store SSH keys in the Azure portal to use when creating VMs in the portal.
To use SSH keys from a Linux or macOS client, see the quick steps. For a more detailed overview of SSH, see Detailed steps: Create and manage SSH keys for authentication to a Linux VM in 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 still leaves the VM vulnerable to brute-force attacks. We recommend connecting to a VM over SSH using a public-private key pair, also known as SSH keys.
The public-private key pair is like the lock on your front door. The lock is exposed to the public, anyone with the right key can open the door. The key is private, and only given to people you trust because it can be used to unlock the door.
The public key is placed on your Linux VM when you create the VM.
The private key remains on your local system. Protect this private key. Do not share it.
When you connect to your Linux VM, the VM tests the SSH client to make sure it has the correct 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 key pair to access multiple Azure VMs and services. You do not need a separate pair of keys for each VM.
Your public key can be shared with anyone, but only you (or your local security infrastructure) should have access to your private key.
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 clients
Recent versions of Windows 10 include OpenSSH client commands to create and use SSH keys and make SSH connections from PowerShell or a command prompt. This is the easiest way to create an SSH connection to your Linux VM, from a Windows computer.
You can also use Bash in the Azure Cloud Shell to connect to your VM. You can use Cloud Shell in a web browser, from the Azure portal, or as a terminal in Visual Studio Code using the Azure Account extension.
You can also install the Windows Subsystem for Linux to connect to your VM over SSH and use other native Linux tools within a Bash shell.
Create an SSH key pair
Create an SSH key pair using the ssh-keygen command. Enter a filename, or use the default shown in parenthesis (for example C:Usersusername/.ssh/id_rsa). Enter a passphrase for the file, or leave the passphrase blank if you do not want to use a passphrase.
Create a VM using your key
To create a Linux VM that uses SSH keys for authentication, provide your SSH public key when creating the VM.
Using the Azure CLI, you specify the path and filename for the public key using az vm create and the --ssh-key-value parameter.
With PowerShell, use New-AzVM and add the SSH key to the VM configuration using`. For an example, see Quickstart: Create a Linux virtual machine in Azure with PowerShell.
If you do a lot of deployments using the portal, you might want to upload your public key to Azure, where it can be easily selected when creating a VM from the portal. For more information, see Upload an SSH key.
Connect to your VM
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 10.111.12.123 in the following command with the administrator user name, the IP address (or fully qualified domain name), and the path to your private key:
If you configured a passphrase when you created your key pair, enter the passphrase when prompted.
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.
Next steps
For information about SSH keys in the Azure portal, see Generate and store SSH keys in the Azure portal to use when creating VMs in the portal.
For detailed steps, options, and advanced examples of working with SSH keys, see Detailed steps to create SSH key pairs.
You can also use PowerShell in Azure Cloud Shell to generate SSH keys and make SSH connections to Linux VMs. See the PowerShell quickstart.
If you have difficulty using SSH to connect to your Linux VMs, see Troubleshoot SSH connections to an Azure Linux VM.
More Linux resources
If you have ever worked as a sysadmin (or you want to in the future), you need a good grasp of SSH. I will not run you through the general concept as it has already been hashed out here at Enable Sysadmin. However, I do want to look at a potentially better way to use it. SSH is the single most used remote access protocol in the world. Therefore, it makes sense that we should try to improve its use as much as possible.
I used SSH to remotely connect to thousands of customer machines during my time as a support engineer, and I am sure that others have had a similar experience. With traditional SSH authentication, you need the username and password for the account you want to log in to every time that you wish to access a system. Doesn't sound that bad, right? But, what happens when you need to jump back and forth between systems regularly? Or what if your responsibilities include remote sessions to the same 100 systems throughout the day for health checks? There is another way to accomplish the log in, and with a little upfront investment, it can be far more efficient overall.
Process hardening
It is objectively true that an encrypted key is a much harder target than a username and password for those with ill intentions. Although it can take a little learning, creating and using SSH key-based authentication is worth the investment for every sysadmin.
Here is how it works. You generate a public key and a matching private key. The private key file acts as a password and should be kept safe. However, the public key is copied to the target systems that you connect to regularly. You place the public key in your account home directory on the target server. When you try to log in, the keys are verified, and access is granted.
Rsa Ssh2
Now, there are two ways that you can do this. One is more convenient, and the other is a bit tedious but with added protection to you. The convenient way is not to specify a password along with the private key. The result is that you do not have to enter a password when you use your private key for authentication. This means that if someone gets their hands on your private key, they can use it to authenticate, as well. The other method is to password-protect your private key so that you are prompted for the password when authenticating (think two-factor authentication using both the private key and the password).
ssh-keygen without a password
To generate an SSH key pair, use the following command:
By default, your private and public keys are saved in your ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub files, respectively.
ssh-keygen with a password
Creating a password-protected key looks something like this:
Use the -f option to specify the file where the keys will be saved. In the example above, the private and public keys are stored in the /home/user/.ssh/key-with-pass and /home/user/.ssh/key-with-pass.pub files, respectively.
Warning
During further SSH key pair generation, if you do not specify a unique file name, you are prompted for permission to overwrite the existing id_rsa and id_rsa.pub files. If you overwrite the existing id_rsa and id_rsa.pub files, you must then replace the old public key with the new one on ALL of the SSH servers that have your old public key.
Once you have generated the keys, they are stored in the /user/home/.ssh/ directory with the following permissions:
- Private key - 600
- Public key - 644
You aren't done yet. Let's look at the final step in successful SSH key-based authentication.
Sharing keys
For all of this to work, you need to share your public key with the remote machines you are trying to SSH to. Use the ssh-copy-id command to copy your public key over to the destination system. By default, the file path is /home/user/.ssh/id_rsa.pub. You issue the command, specify the file you are sharing, then the user/host we are sharing it with. It should look like this:
Now that you have shared the public key with the destination host, you can authenticate to the remote server by passing the matching private key. If you specified a file path for your private key, you need to give it here. Otherwise, it defaults to /home/_user_/.ssh/id_rsa.
Seen here:
Advantages and summary
The advantages of using SSH key-based authentication are clear. Passwords are stolen every day, mainly due to human error but also due to attacker skill and determination. An encrypted key, and more specifically, a password-protected encrypted key, makes your SSH authentication even more difficult to attack. You still need to strike a balance of availability and security, but that is handled differently in every environment.
Ssh Using Rsa Key
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Ubuntu Generate Ssh Rsa Key
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