Generate Ssh Public Key Centos

09.04.2020by

Introduction

  1. How To Generate Ssh Key Centos
  2. Centos Ssh Key Setup
  3. Generate Ssh Public Key Centos Download
  4. Generate Ssh Public Key Centos 10

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.

With both Tectia SSH and OpenSSH servers, access to an account is granted by adding the public key to a /.ssh/authorizedkeys file on the server. To install the public key, Log into the server, edit the authorizedkeys file with your favorite editor, and cut-and-paste the public key output by the above command to the authorizedkeys file. Generating Your SSH Public Key. Many Git servers authenticate using SSH public keys. In order to provide a public key, each user in your system must generate one if they don’t already have one. This process is similar across all operating systems. First, you should check to make sure you don’t already have a key.

Camtasia studio 8 key generator free download. Using SSH keys for authentication is highly recommended, as a safer alternative to passwords.

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This tutorial will guide you through the steps on how to generate and set up SSH keys on CentOS 7. We also cover connecting to a remote server using the keys and disabling password authentication.

1. Check for Existing Keys

Prior to any installation, it is wise to check whether there are any existing keys on the client machines.

Open the terminal and list all public keys stored with the following command:

The output informs you about any generated keys currently on the system. If there aren’t any, the message tells you it cannot access /.ssh/id_*.pub , as there is no such file or directory.

2. Verify SSH is Installed

To check if thw package is installed, run the command:

If you already have SSH, the output tells you which version it is running. Currently, the latest version is OpenSSH 8.0/8.0p1.

Note: Refer to our guide If you need to install and enable SSH on your CentOS system.

Steps to Creating SSH keys on CentOS

Step 1: Create SSH Key Pair

1. Start by logging into the source machine (local server) and creating a 2048-bit RSA key pair using the command:

If you want to tighten up security measures, you can create a 4096-bit key by adding the -b 4096 flag:

2. After entering the command, you should see the following prompt:

3. To save the file in the suggested directory, press Enter. Alternatively, you can specify another location.

Note: If you already have a key pair in the proposed location, it is advisable to pick another directory. Otherwise it will overwrite existing SSH keys.

4. Next, the prompt will continue with:

Although creating a passphrase isn’t mandatory, it is highly advisable.

5. Finally, the output will end by specifying the following information:

Now you need to add the public key to the remote CentOS server.

You can copy the public SSH key on the remote server using several different methods:

  1. using the ssh-copy-id script
  2. using Secure Copy (scp)
  3. manually copying the key

The fastest and easiest method is by utilizing ssh-copy-id. If the option is available, we recommend using it. Otherwise, try any of the other two noted.

1. Start by typing the following command, specifying the SSH user account, and the IP address of the remote host:

If it is the first time your local computer is accessing this specific remote server you will receive the following output:

2. Confirm the connection – type yes and hit Enter.

3. Once it locates the id_rsa.pub key created on the local machine, it will ask you to provide the password for the remote account. Type in the password and hit Enter.

4. Once the connection has been established, it adds the public key on the remote server. This is done by copying the ~/.ssh/id_rsa.pub file to the remote server’s ~/.ssh directory. You can locate it under the name authorized_keys.

5. Lastly, the output tells you the number of keys added, along with clear instructions on what to do next:

1. First, set up an SSH connection with the remote user:

2. Next, create the ~/.ssh directory as well as the authorized_keys file:

3. Use the chmod command to change the file permission:

chmod 700 makes the file executable, while chmod 600 allows the user to read and write the file.

4. Now, open a new terminal session, on the local computer.

5. Copy the content from id_rsa.pub (the SSH public key) to the previously created authorized_keys file on the remote CentOS server by typing the command:

With this, the public key has been safely stored on the remote account.

1. To manually add the public SSH key to the remote machine, you first need to open the content from the ~/.ssh/id_rsa.pub file:

How To Generate Ssh Key Centos

2. As in the image below, the key starts with ssh-rsa and ends with the username of the local computer and hostname of the remote machine:


3. Copy the content of the file, as you will need later.

4. Then, in the terminal window, connect to the remote server on which you wish to copy the public key. Use the following command to establish the connection:

5. Create a ~/.ssh directory and authorized_keys file on the CentOS server with the following command:

6. Change their file permission by typing:

7. Next, open the authorized_keys file with an editor of your preference. For example, to open it with Nano, type:

8. Add the public key, previously copied in step 2 of this section, in a new line in (under the existing content).

9. Save the changes and close the file.

10. Finally, log into the server to verify that everything is set up correctly.

Once you have completed the previous steps (creating an RSA Key Pair and copying the Public Key to the CentOS server), you will be able to connect to the remote host without typing the password for the remote account.

All you need to do is type in the following command:

If you didn’t specify a passphrase while creating the SSH key pair, you will automatically log in the remote server.

Otherwise, type in the passphrase you supplied in the initial steps and press Enter.

Once the shell confirms the key match, it will open a new session for direct communication with the server.

Although you managed to access the CentOS server without having to provide a password, it still has a password-based authentication system running on the machine. This makes it a potential target for brute force attacks.

You should disable password authentication entirely by following the outlined steps.

Note: Consider performing the following steps through a non-root account with sudo privileges, as an additional safety layer.

1. Using the SSH keys, log into the remote CentOS server which has administrative privileges:

2. Next, open the SSH daemon configuration file using a text editor of your choice:

3. Look for the following line in the file:

4. Edit the configuration by changing the yes value to no. Thus, the directive should be as following:

5. Save the file and exit the text editor.
6. To enable the changes, restart the sshdservice using the command:

7. Verify the SSH connection to the server is still functioning correctly. Open a new terminal window and type in the command:

In this article, you learned how to generate SSH key pairs and set up an SSH key-based authentication. We also covered copying keys to your remote CentOS server, and disabling SSH password authentication.

Next, You Should Read:

SSH keys can serve as a means of identifying yourself to an SSH server using public-key cryptography and challenge-response authentication. The major advantage of key-based authentication is that in contrast to password authentication it is not prone to brute-force attacks and you do not expose valid credentials, if the server has been compromised.

Centos Ssh Key Setup

Furthermore SSH key authentication can be more convenient than the more traditional password authentication. When used with a program known as an SSH agent, SSH keys can allow you to connect to a server, or multiple servers, without having to remember or enter your password for each system.

Key-based authentication is not without its drawbacks and may not be appropriate for all environments, but in many circumstances it can offer some strong advantages. A general understanding of how SSH keys work will help you decide how and when to use them to meet your needs.

In this guide, we’ll set up SSH keys for a CentOS 7

Generate a Key Pair

  • Open Terminal

You now have a public and private key that you can use to authenticate. The next step is to place the public key on your server so that you can use SSH-key-based authentication to log in.

Upload your Public Key

There are a few different ways to upload your public key

1. Using ssh-copy-id

ssh-copy-id is a utility available on some operating systems that can copy a SSH public key to a remote server over SSH.

Now try logging into the machine, with: “ssh ‘[email protected]remote_host‘ “ and check to make sure that only the key(s) you wanted were added.

2. Using Secure Copy (scp)

Secure Copy (scp) is a tool that copies files from a local computer to a remote server over SSH

Connect to your server via SSH with the user you would like to add your key to:

Create the ~/.ssh directory and authorized_keys file if they don’t already exist:

Give the ~/.ssh directory and authorized_keys files appropriate file permissions:

In terminal on your local machine, use scp to copy the contents of your SSH publickey(id_rsa.pub) into the authorized_keys file on your server.

Now you can log in to the server with your key.

3. Copying Public Key Manually

If you do not have password-based SSH access to your server available, you will have to complete the above process manually.

We will manually append the content of your id_rsa.pub file to the ~/.ssh/authorized_keys file on your remote machine.

To display the content of your id_rsa.pub key, type this into your local computer:

Note that the public key begins with ssh-rsa and ends with [email protected]

Copy that text, connect to your server via SSH with the user you would like to add your key to:

Create the~/.ssh directory and authorized_keys file if they don’t already exist:

Give the ~/.ssh directory and authorized_keys files appropriate file permissions:

Open the authorized_keys file with the text editor. Then, paste the contents of your public key that you copied in step one on a new line at the end of the file. Save and close the file.

Now you can log in to the server with your key.

Generate Ssh Public Key Centos Download

Creating SSH shortcuts

Instead of using SSH on an IP address that you’ll definitely forget, you can use shortcuts instead

Add an entry for each computer you want to connect to, like this:

Now, you can ssh into the server with the shortcut.

Generate Ssh Public Key Centos 10

Ssh

You should now have SSH-key-based authentication configured on your server, allowing you to sign in without providing an account password.

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