Ssh keygen

Notes

To generate an SSH key pair for login into a CentOS 7 server, you can follow these steps:
Open a terminal on your local machine.
Type the following command to generate a new SSH key pair:
```
 ssh-keygen
```
This will prompt you for a file name to save the key pair, and a passphrase (which is optional). Press "Enter" to accept the default file name and location, and then enter a passphrase if you want to use one.
Once the key pair has been generated, you should see two new files in the location you specified:

id_rsa (the private key)

id_rsa.pub (the public key)

ssh-copy-id user@server-ip

Replace user with your username on the CentOS 7 server, and server-ip with the IP address of the server.
This command will copy the public key to the server and add it to the authorized_keys file, which will allow you to log in using the private key.
Log in to the CentOS 7 server using the private key:
```
ssh user@server-ip -i ~/.ssh/id_rsa
```
This command will log you in to the server using the private key that you just generated.
That's it! You should now be able to log in to your CentOS 7 server using the SSH key pair.

================================

Run the following command to generate the SSH key:

ssh-keygen -t rsa -b 4096 -f /root/.ssh/id_rsa

This command will generate a 4096-bit RSA key and save it in the root user's .ssh directory with the filename id_rsa.
When prompted, enter a passphrase for the key or leave it blank if you do not want to set one.
Repeat step 2 to generate a second SSH key with a different name (e.g. id_rsa_second).
Copy the public key of each SSH key pair (id_rsa.pub and id_rsa_second.pub) to the remote servers or services that you want to connect to using SSH.
For example, to copy the id_rsa.pub file to a remote server, run the following command:
```
ssh-copy-id -i /root/.ssh/id_rsa.pub user@remote-server
```
Replace user with the username on the remote server and remote-server with the hostname or IP address of the remote server.
Repeat the command for each public key you want to copy to remote servers.
Test the SSH connection using each SSH key by running the following command:
```
ssh -i /root/.ssh/id_rsa user@remote-server
```
Replace id_rsa with the name of the SSH key file you want to use and user and remote-server with the appropriate values for the remote server.
Repeat the command for each SSH key you want to test.
That's it! You now have two SSH keys for the root user that you can use to securely connect to remote servers and services.