Ssh Generate Host Keys Centos 6
Ssh Generate Host Keys Centos 7
Centos Ssh Keygen

Jan 22, 2021 Step 1: Generate SSH Public/Private Key Pair on CentOS/RHEL Desktop. On your CentOS/RHEL desktop (not your server), enter the following command in a terminal window. Ssh-keygen -t rsa -b 4096. Where:-t stands for type. The above command generates an RSA type keypair. RSA is the default type.-b stands for bits. By default, the key is 3072 bits long. See full list on digitalocean.com.

Introduction & Description

By default, ssh-keygen will create a 2048-bit RSA key pair, which is secure enough for most use cases (you may optionally pass in the -b 4096 flag to create a larger 4096-bit key). After entering the command, you should see the following prompt.

Do not give out, store remotely or otherwise expose your private key to the outside world or you defeat the purpose entirely of using encrypted keys. Doing so is the equivalent to locking the door to your house and leaving the keys in the handle for anyone to use/take.

We’ll be using RSA in this example however, you’re perfectly welcome and able to use DSA if you so choose. The difference is RSA, by default, uses a 2048 bit key and canbe up to 4096 bits, while DSA keys must be exactly 1024 bits as specified by FIPS 186-2. It is recommended to use a 4096 bit key as a matter of habit in today’s world where personal and private digital security is often in question, never view yourself or your systems as invulnerable and always take the strongest precautions that are available to you.

With that said we’ll give the following command to create our public/private keypair:

Doing the Work

Ssh Generate Host Keys Centos 6

Create your public and private keypair using ssh-keygen:

(you will have a public key that you copy to the computers you’ll be accessing, and a private key that does not leave your system ever.)
cd ~/.ssh
ssh-keygen -t rsa -b 4096

</div><div><table><tbody><tr><td><div><div>2</div><div>4</div><div>6</div><div>8</div><div>10</div><div>12</div><div>14</div><div>16</div><div>18</div><div>20</div></div></td><td><div><div><span>Enter </span><span>file </span><span>in</span><span>which </span><span>to</span><span>save </span><span>the </span><span>key</span><span>(</span><span>/</span><span>home</span><span>/</span><span>warren</span><span>/</span><span>.</span><span>ssh</span><span>/</span><span>id_rsa</span><span>)</span><span>:</span><span>example_id_rsa</span></div><div><span>Enter </span><span>same </span><span>passphrase </span><span>again</span><span>:</span></div><div><span>Your </span><span>identification </span><span>has </span><span>been </span><span>saved </span><span>in</span><span>example_id_rsa</span><span>.</span></div><div><span>Your </span><span>public</span><span>key </span><span>has </span><span>been </span><span>saved </span><span>in</span><span>example_id_rsa</span><span>.</span><span>pub</span><span>.</span></div><div><span>80</span><span>:</span><span>b9</span><span>:</span><span>33</span><span>:</span><span>07</span><span>:</span><span>27</span><span>:</span><span>22</span><span>:</span><span>cb</span><span>:</span><span>5a</span><span>:</span><span>be</span><span>:</span><span>ae</span><span>:</span><span>07</span><span>:</span><span>d1</span><span>:</span><span>79</span><span>:</span><span>de</span><span>:</span><span>23</span><span>:</span><span>28</span><span>warren</span><span>@</span><span>quetzal</span></div><div><span>+</span><span>--</span><span>[</span><span>RSA</span><span>4096</span><span>]</span><span>--</span><span>--</span><span>+</span></div><div><span>|</span><span>o</span><span>|</span></div><div><span>|</span><span>ooo</span><span>.</span><span>.</span><span>=</span><span>.</span><span>|</span></div><div><span>|</span><span>Eo</span><span>.</span><span>o</span><span>+</span><span>o</span><span>|</span></div><div><span>|</span><span>.</span><span>.</span><span>|</span></div><div><span>+</span><span>--</span><span>--</span><span>--</span><span>--</span><span>--</span><span>--</span><span>--</span><span>--</span><span>-</span><span>+</span></div></div></td></tr></tbody></table></div></div><p><em><strong>Private</strong> Keyfile: <code>example_id_rsa</code><br /><em>Public</em> Keyfile: <code>example_id_rsa.pub</code></em></p><div><em><strong>IMPORTANT:</strong> The <em>.ssh directory must have a permission of 700</em> and the <em>authorized_keys file within that directory must have a permission of 600</em> to work for passwordless entry (there will be a password for the key itself). To accomplish this give the following commands as the user you will be using to ssh with:<p><code>chmod 700 ~/.ssh; chmod 600 ~/.ssh/authorized_keys</code></p><p><em>note:</em> If you’re using a laptop which has the possibility of being lost or stolen or you’re using several systems, you may consider using separate public/private keypairs and simply update/add to the authorized_keys file on the target systems. Remember that the private key should never leave the machine it was created on. If the laptop is then lost or stolen you can simply remove the reference to the key on the target machines authorized_keys file. You’ll need to use a naming system that allows you to quickly identify which key belongs to which host(s) as well.</p><p><em>Here are some simple examples:</em></p><p><cite>Enter file in which to save the key (/home/user/.ssh/id_rsa):</cite><br /><em>id_rsa.dev<br /> id_rsa.laptop<br /> id_rsa.desktop<br /> id_rsa.work</em></p></em></div><li><em>Copy your ~/.ssh/example_id_rsa.pub on the local system to ~/.ssh/authorized_keys on the remote system ising <strong>ssh-copy-id</strong>:</em></li><p><em><code>[user@localhost .ssh]$ ssh-copy-id -i example_id_rsa.pub 192.168.0.2</code></em></p><div><em><strong>Output:</strong><br /> user@192.168.0.2’s password:<p>Now try logging into the machine, with “ssh ‘192.168.0.2’”, and check in:<br /> ~/.ssh/authorized_keys<br /> to make sure we haven’t added extra keys that you weren’t expecting.</p></em></div><li><em>Attempt to login</em></li><p><em><code>[user@localhost .ssh]$ ssh 192.168.0.2</code></em></p><div><em><strong>Output:</strong><br /> Enter passphrase for key ‘/home/user/.ssh/example_id_rsa’:<br /> Last login: Tue Mar 23 16:04:23 2010 from foo.comcast.net<br /> [user@remotehost]$</em></div><li><em>Setting up ssh for automatic passwordless login with keys using <strong>ssh-agent</strong> and <strong>ssh-add</strong>:</em></li><p><em><strong>add these lines at the bottom of your .bash_profile:</strong><br /><code>vi ~/.bash_profile</code></em></p><div><em><strong>Output:</strong><br /> SSHAGENT=/usr/bin/ssh-agent<br /> SSHAGENTARGS=”-s”<br /> if [ -z “$SSH_AUTH_SOCK” -a -x “$SSHAGENT” ]; then<br /> eval <code>$SSHAGENT $SSHAGENTARGS</code><br /> trap “kill $SSH_AGENT_PID” 0<br /> fi</em></div><p><em><strong>Next, logout/login or give the command:</strong><br /><code>source ~/.bash_profile</code></em></p><li><em>Add private key identity to the local authentication agent, so we don’t need to enter our password everytime.</em></li><p><em>[user@localhost ~]$ ssh-add<br /> Enter passphrase for /home/user/.ssh/example_id_rsa:<br /> Identity added: /home/user/.ssh/id_rsa (/home/user/.ssh/example_id_rsa)</em></p><li><em>Connect to the remote system</em></li><p><em>[user@localhost ~]$ ssh 192.168.0.2<br /> Last login: Tue Mar