If your SSH client supports it, you can use public key authentication to log into Bitvise SSH Server. On Windows, we recommend Bitvise SSH Client, which has strong support for public key authentication, as well as password authentication, and Kerberos single sign-on in domain environments.

• Ssh Server Public Key Too Small Nmap
• Ssh Public Key Linux

A tutorial on configuring SSH Server to Authenticate with Private/Public Keys using Ubuntu Linux http://www.danscourses.com/Linux-Fundamentals/how. To import a public key into the SSH Server this way: Use the SSH Client to connect to the SSH Server using the account for which you want to configure the public key. Once connected, open Client key manager. Right-click on the keypair, and select Upload to server. To import a public key into the SSH Server this way. Use the SSH Client to connect to the SSH Server using the account for which you want to configure. Putty-SSH-Auth-Browse to your private. Ensure you have the same path for private and public key. You need to configure the public key on the server. (In my case I've talked with the server guy and asked if he could add my public key to the server). You need the public key in the other side (server.

If you are new to public key authentication, we first suggest reading Public keys in SSH.

To set up public key authentication, you first need to generate a keypair on the client, or select one or more existing keypairs for use with client authentication. The procedure for generating the keypair depends on the client software being used:

• If you are using Bitvise SSH Client, click the link titled Client key manager in the Login tab. You can generate, edit, import and export keypairs in the dialog box that pops up.
• If you are using a different client, you need to follow its process for generating keypairs. For example, in OpenSSH, keypairs are generated using the ssh-keygen utility. Make sure to generate an SSH2 keypair (not SSH1). Use either the ECDSA, RSA, or DSA (DSS) algorithms. We recommend either ECDSA, or RSA with a size of 2048 bits or higher.

Once the keypair has been generated, you need to import the public key (not the whole keypair!) into the SSH Server.

Recent Bitvise SSH Server and SSH Client versions support the SSH Public Key Subsystem. To import a public key into the SSH Server this way:

• Use the SSH Client to connect to the SSH Server using the account for which you want to configure the public key.
• Once connected, open Client key manager. Right-click on the keypair, and select Upload to server.
• You should now be able to authenticate using this keypair.

You can also use this feature to manage keys in the SSH Server from the command line, using the spksc client included with Bitvise SSH Client.

With most clients, you can export the public key into a file, transfer the file to the SSH Server, and import it into SSH Server settings. In this case:

• Export the public key in either the standard SSH2 public key format, or in the OpenSSH format. If you are using OpenSSH, the public key file can be exported from an existing keypair using the ssh-keygen utility (consult 'man ssh-keygen').
• Once your public key file has been exported, transfer it to the machine where Bitvise SSH Server is installed, or a machine from which you manage the SSH Server remotely using Bitvise SSH Client.
• Use either Easy SSH Server settings (screenshot) or Advanced settings (screenshot) to import the public key into the SSH user's account settings entry.

Common mistakes: Make sure that you don't try to import the client's key into the server's host key management interface. The host key management interface is accessed directly from the 'Server' tab of the Bitvise SSH Server Control Panel, and is intended to manage keypairs that authenticate the server. These keypairs are separate and unrelated to client authentication.

For Windows accounts, the SSH Server also supports synchronization with ~/.ssh/authorized_keys. This feature must be enabled in Advanced SSH Server settings, under Access control. It allows Windows users to upload their SSH public key to a file named authorized_keys under a subdirectory named .ssh under the user's Windows profile directory. If this setting is enabled, the SSH Server will check for the existence of the authorized_keys file when the user logs out. If the file exists, the SSH Server will replace all of the public keys configured for the user with keys found in this file.

Use this feature with caution: if your system has unused authorized_keys files laying around, this may cause public keys to be unexpectedly deleted.

With a secure shell (SSH) key pair, you can create virtual machines (VMs) in Azure that use SSH keys for authentication. This article shows you how to quickly generate and use an SSH public-private key file pair for Linux VMs. You can complete these steps with the Azure Cloud Shell, a macOS or Linux host.

Note

VMs created using SSH keys are by default configured with passwords disabled, which greatly increases the difficulty of brute-force guessing attacks.

For more background and examples, see Detailed steps to create SSH key pairs.

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

Create an SSH key pair

Use the ssh-keygen command to generate SSH public and private key files. By default, these files are created in the ~/.ssh directory. You can specify a different location, and an optional password (passphrase) to access the private key file. If an SSH key pair with the same name exists in the given location, those files are overwritten.

The following command creates an SSH key pair using RSA encryption and a bit length of 4096:

If you use the Azure CLI to create your VM with the az vm create command, you can optionally generate SSH public and private key files using the --generate-ssh-keys option. The key files are stored in the ~/.ssh directory unless specified otherwise with the --ssh-dest-key-path option. If an ssh key pair already exists and the --generate-ssh-keys option is used, a new key pair will not be generated but instead the existing key pair will be used. In the following command, replace VMname and RGname with your own values:

Provide an SSH public key when deploying a VM

To create a Linux VM that uses SSH keys for authentication, specify your SSH public key when creating the VM using the Azure portal, Azure CLI, Azure Resource Manager templates, or other methods:

If you're not familiar with the format of an SSH public key, you can display your public key with the following cat command, replacing ~/.ssh/id_rsa.pub with the path and filename of your own public key file if needed:

A typical public key value looks like this example:

If you copy and paste the contents of the public key file to use in the Azure portal or a Resource Manager template, make sure you don't copy any trailing whitespace. To copy a public key in macOS, you can pipe the public key file to pbcopy. Similarly in Linux, you can pipe the public key file to programs such as xclip.

The public key that you place on your Linux VM in Azure is by default stored in ~/.ssh/id_rsa.pub, unless you specified a different location when you created the key pair. To use the Azure CLI 2.0 to create your VM with an existing public key, specify the value and optionally the location of this public key using the az vm create command with the --ssh-key-values option. In the following command, replace myVM, myResourceGroup, UbuntuLTS, azureuser, and mysshkey.pub with your own values:

If you want to use multiple SSH keys with your VM, you can enter them in a space-separated list, like this --ssh-key-values sshkey-desktop.pub sshkey-laptop.pub.

SSH into your VM

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

Ssh Server Public Key Too Small Nmap

If you specified a passphrase when you created your key pair, enter that passphrase when prompted during the login process. The VM is added to your ~/.ssh/known_hosts file, and you won't be asked to connect again until either 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.

Next steps

Ssh Public Key Linux

• For more information on working with SSH key pairs, see Detailed steps to create and manage SSH key pairs.

• If you have difficulties with SSH connections to Azure VMs, see Troubleshoot SSH connections to an Azure Linux VM.