1. Do I Need Host Public Key Before Generating User Ssh Code
2. What Is Public Key
3. Do I Need Host Public Key Before Generating User Ssh Server
4. Public Key Example

Oct 20, 2014 Copying your Public Key Using SSH. If you do not have ssh-copy-id available, but you have password-based SSH access to an account on your server, you can upload your keys using a conventional SSH method. We can do this by outputting the content of our public SSH key on our local computer and piping it through an SSH connection to the remote server. How SSH key authentication works. SSH public key authentication works with an asymmetric pair of generated encryption keys. The public key is shared with Azure DevOps and used to verify the initial ssh connection. The private key is kept safe and secure on your system. Set up SSH key authentication. My guess is that a machine running ssh server keeps a mapping of a ssh public key to my user name (I am a remote user) who has authorized access. But a few other people and I are also able to login on behalf of some local user to the remote machine (meaning that we have a remote machine with a local user john.doe to that machine). Overview Public key authentication is a way of logging into an SSH/SFTP account using a cryptographic key rather than a password. If you use very strong SSH/SFTP passwords, your accounts are already safe from brute force attacks. However, using public key authentication provides many benefits when working with multiple developers. For example, with SSH keys you can allow multiple developers to.

Azure Repos Azure DevOps Server 2019 TFS 2018 TFS 2017 TFS 2015 Update 3

Connect to your Git repos through SSH on macOS, Linux, or Windows to securely connect using HTTPS authentication. On Windows, we recommended the use of Git Credential Managers or Personal Access Tokens.

Important

SSH URLs have changed, but old SSH URLs will continue to work. If you have already set up SSH, you should update your remote URLs to the new format:

• Verify which remotes are using SSH by running git remote -v in your Git client.
• Visit your repository on the web and select the Clone button in the upper right.
• Select SSH and copy the new SSH URL.
• In your Git client, run: git remote set-url <remote name, e.g. origin> <new SSH URL>. Alternatively, in Visual Studio, go to Repository Settings, and edit your remotes.

Note

As of Visual Studio 2017, SSH can be used to connect to Git repos.

How SSH key authentication works

SSH public key authentication works with an asymmetric pair of generated encryption keys. The public key is shared with Azure DevOps and used to verify the initial ssh connection. The private key is kept safe and secure on your system.

Set up SSH key authentication

The following steps cover configuration of SSH key authentication on the following platforms:

• Linux
• macOS running at least Leopard (10.5)
• Windows systems running Git for Windows

Configure SSH using the command line. bash is the common shell on Linux and macOS and the Git for Windows installation adds a shortcut to Git Bash in the Start menu.Other shell environments will work, but are not covered in this article.

Step 1: Create your SSH keys

Note

If you have already created SSH keys on your system, skip this step and go to configuring SSH keys.

The commands here will let you create new default SSH keys, overwriting existing default keys. Before continuing, check your~/.ssh folder (for example, /home/jamal/.ssh or C:Usersjamal.ssh) and look for the following files:

• id_rsa
• id_rsa.pub

If these files exist, then you have already created SSH keys. You can overwrite the keys with the following commands, or skip this step and go to configuring SSH keys to reuse these keys.

Create your SSH keys with the ssh-keygen command from the bash prompt. This command will create a 2048-bit RSA key for use with SSH. You can give a passphrasefor your private key when prompted—this passphrase provides another layer of security for your private key.If you give a passphrase, be sure to configure the SSH agent to cache your passphrase so you don't have to enter it every time you connect.

This command produces the two keys needed for SSH authentication: your private key ( id_rsa ) and the public key ( id_rsa.pub ). It is important to never share the contents of your private key. If the private key iscompromised, attackers can use it to trick servers into thinking the connection is coming from you.

Step 2: Add the public key to Azure DevOps Services/TFS

Associate the public key generated in the previous step with your user ID.

1. Open your security settings by browsing to the web portal and selecting your avatar in the upper right of theuser interface. Select Security in the menu that appears.

2. Select SSH public keys, and then select + New Key.

3. Copy the contents of the public key (for example, id_rsa.pub) that you generated into the Public Key Data field.

   Important

   Avoid adding whitespace or new lines into the Key Data field, as they can cause Azure DevOps Services to use an invalid public key. When pasting in the key, a newline often is added at the end. Be sure to remove this newline if it occurs.

4. Give the key a useful description (this description will be displayed on the SSH public keys page for your profile) so that you can remember it later. Select Save to store the public key. Once saved, you cannot change the key. You can delete the key or create a new entry for another key. There are no restrictions on how many keys you can add to your user profile.

Step 3: Clone the Git repository with SSH

Note

To connect with SSH from an existing cloned repo, see updating your remotes to SSH.

1. Copy the SSH clone URL from the web portal. In this example, the SSL clone URL is for a repo in an organization named fabrikam-fiber, as indicated by the first part of the URL after dev.azure.com.

   Note

   Project URLs have changed with the release of Azure DevOps Services and now have the format dev.azure.com/{your organization}/{your project}, but you can still use the existing visualstudio.com format. For more information, see VSTS is now Azure DevOps Services.

2. Run git clone from the command prompt.

SSH may display the server's SSH fingerprint and ask you to verify it.

For cloud-hosted Azure DevOps Services, where clone URLs contain either ssh.dev.azure.com or vs-ssh.visualstudio.com, the fingerprint should match one of the following formats:

• MD5: 97:70:33:82:fd:29:3a:73:39:af:6a:07:ad:f8:80:49 (RSA)
• SHA256: SHA256:ohD8VZEXGWo6Ez8GSEJQ9WpafgLFsOfLOtGGQCQo6Og (RSA)These fingerprints are also listed in the SSH public keys page.

For self-hosted instances of Azure DevOps Server, you should verify that the displayed fingerprint matches one of the fingerprints in the SSH public keys page.

SSH displays this fingerprint when it connects to an unknown host to protect you from man-in-the-middle attacks.Once you accept the host's fingerprint, SSH will not prompt you again unless the fingerprint changes.

When you are asked if you want to continue connecting, type yes. Git will clone the repo and set up the origin remote to connect with SSH for future Git commands.

Tip

Avoid trouble: Windows users will need to run a command to have Git reuse their SSH key passphrase.

Questions and troubleshooting

Q: After running git clone, I get the following error. What should I do?

Host key verification failed.fatal: Could not read from remote repository.

A: Manually record the SSH key by running:ssh-keyscan -t rsa domain.com >> ~/.ssh/known_hosts

Q: How can I have Git remember the passphrase for my key on Windows?

A: Run the following command included in Git for Windows to start up the ssh-agent process in Powershell or the Windows Command Prompt. ssh-agent will cacheyour passphrase so you don't have to provide it every time you connect to your repo.

If you're using the Bash shell (including Git Bash), start ssh-agent with:

Q: I use PuTTY as my SSH client and generated my keys with PuTTYgen. Can I use these keys with Azure DevOps Services?

A: Yes. Load the private key with PuTTYgen, go to Conversions menu and select Export OpenSSH key.Save the private key file and then follow the steps to set up non-default keys.Copy your public key directly from the PuTTYgen window and paste into the Key Data field in your security settings.

Q: How can I verify that the public key I uploaded is the same key as I have locally?

A: You can verify the fingerprint of the public key uploaded with the one displayed in your profile through the following ssh-keygen command run against your public key usingthe bash command line. You will need to change the path and the public key filename if you are not using the defaults.

You can then compare the MD5 signature to the one in your profile. This check is useful if you have connection problems or have concerns about incorrectlypasting in the public key into the Key Data field when adding the key to Azure DevOps Services.

Q: How can I start using SSH in a repository where I am currently using HTTPS?

A: You'll need to update the origin remote in Git to change over from a HTTPS to SSH URL. Once you have the SSH clone URL, run the following command:

You can now run any Git command that connects to origin.

Q: I'm using Git LFS with Azure DevOps Services and I get errors when pulling files tracked by Git LFS.

A: Azure DevOps Services currently doesn't support LFS over SSH. Use HTTPS to connect to repos with Git LFS tracked files.

Q: How can I use a non default key location, i.e. not ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub?

A: To use keys created with ssh-keygen in a different place than the default, you do two things:

1. The keys must be in a folder that only you can read or edit. If the folder has wider permissions, SSH will not use the keys.
2. You must let SSH know the location of the keys. You make SSH aware of keys through the ssh-add command, providing the full path to the private key.

On Windows, before running ssh-add, you will need to run the following command from included in Git for Windows:

This command runs in both Powershell and the Command Prompt. If you are using Git Bash, the command you need to use is:

You can find ssh-add as part of the Git for Windows distribution and also run it in any shell environment on Windows.

On macOS and Linux you also must have ssh-agent running before running ssh-add, but the command environment on these platforms usuallytakes care of starting ssh-agent for you.

Q: I have multiple SSH keys. How do I use different SSH keys for different SSH servers or repos?

A: Generally, if you configure multiple keys for an SSH client and connect to an SSH server, the client can try the keys one at a time until the server accepts one.

Do I Need Host Public Key Before Generating User Ssh Code

However, this doesn't work with Azure DevOps for technical reasons related to the SSH protocol and how our Git SSH URLs are structured. Azure DevOps will blindly accept the first key that the client provides during authentication. If that key is invalid for the requested repo, the request will fail with the following error:

For Azure DevOps, you'll need to configure SSH to explicitly use a specific key file. One way to do this to edit your ~/.ssh/config file (for example, /home/jamal/.ssh or C:Usersjamal.ssh) as follows:

Q: What notifications may I receive about my SSH keys?

A: Whenever you register a new SSH Key with Azure DevOps Services, you will receive an email notification informing you that a new SSH key has been added to your account.

Q: What do I do if I believe that someone other than me is adding SSH keys on my account?

A: If you receive a notification of an SSH key being registered and you did not manually upload it to the service, your credentials may have been compromised.

The next step would be to investigate whether or not your password has been compromised. Changing your password is always a good first step to defend against this attack vector. If you’re an Azure Active Directory user, talk with your administrator to check if your account was used from an unknown source/location.

In order to use public and private key based authentication to SFTP to your server, you need to have SSH enabled on your hosting account. Most hosts do not enable SSH by default, so you might want to check with your host and get it enabled if it isn't already. Once SSH is enabled, connecting to your server is simple. Here are three main steps involved:

1. Generating public and private Key pairs using Cpanel.
2. Downloading and converting the private key into PPK (PuTTY Private Key) format.
3. Connecting to your server using an FTP client and using the PPK key for authentication.

So let's look at these steps in details:

Generating Public and Private Key Pairs Using Cpanel

In order to use SFTP, we first need to generate public and private key pairs. This can easily be done using Cpanel as detailed in the steps below:

Step 1:Login to Your Cpanel and click on SSH Shell Access under the security section.

Step 2: Click on the Manage SSH Keys button and then Click on the Generate a New Key link.

Step 3: On this page, enter the following details:

Once all details are entered, click on Generate Key (refer image above). This will generate a public and private key pair. You should now be able to see these files in your Manage SSH Keys page.

Step 4: On the Manage SSH Keys page, click on Manage Authorization and then click the Authorize button. This will authorize the key for usage as shown in the image below.

Step 5: Click on the View or Download link in the Private Keys section to covert and download your private key.

Converting Private Key to PPK Format

We now need to convert the private key to PPK format. You can do this using the covert key option on Cpanel, or you can download the raw file and covert it to PPK format using PuttyGen. In most cases, the Cpanel convert option works pretty good, so you can stick with it. But in-case, you don't have that option in your Cpanel account, you can use the Puttygen method. Let's look at both these methods:

Option 1: Converting the key to PPK format using Cpanel Covert key option:

To use this option, enter your passphrase in the space provided and click Convert as shown in the image below. You can then download the converted key to your computer and save it in an accessible location.

Note: The passpharse is the key password that you used while generating the keys in Cpanel.

Option 2: Converting the Key to PPK format Using PuttyGen:

/finding-nest-3rd-generation-key-pin.html. This option involves using PuttyGen to convert the key. If you don't have PuttyGen installed, you can download it free from here. Once downloaded and installed, follow these steps:

What Is Public Key

Step 1: As shown in the image above (marked Option 2), click on the 'Download Key' button on the View or Download SSH Keys page. This will download the private key (id_rsa) to your computer. Copy and save this file in an accessible location.

Step 2: Open the PuttyGen application and click Run.

Step 3: Go to Conversions > Import Key, browse to the location of your downloaded private key file (id_rsa) and select the file.

Once you load the file you will be prompted to enter the passpharse. Enter the passpharse and click ok.

Step 4: Make sure that the SSH2 RSA option is selected and the number of bits is set to 2048.

Step 5: Click on Save private key and save the file with your preferred name. (Refer image above).

SFTP to the Server

Now that we have our public and private keys setup, we can SFTP to the server. You can do this using any FTP client like Filezilla or WinSCP. I am using WinSCP for this tutorial.

Step 1: Open WinSCP and create a new FTP connected by clicking on New Site and enter the following details:

Do I Need Host Public Key Before Generating User Ssh Server

Step 2: Click on the Advanced botton to open the Advanced Site Settings page as shown in point no.6 in the image above.

Step 3: On the Advanced Site Settings page click on Authentication and then browse to the location of your PPk file. Refer image below:

Step 4: Once done, click ok and then click Save to save the settings.

Step 5: Click Login to login to your server using SFTP. Once the connection is establised and the server has finished verifing the private and public keys, you will be promoted to enter the passpharse. Enter the passpharse and click Ok.

Public Key Example

You should now be connected to your server using SFTP.